UPSC Geo-Scientist Prelims 2021 Chemistry (Paper II): answer key and solutions

The number of radial nodes for 2s, 3p and 3d orbitals, respectively are:

1. (a) 2, 1, 0
2. (b) 2, 1, 1
3. (c) 1, 0, 0
4. (d) 1, 1, 0

What fraction of the total number of electrons is in the p-sublevels in Iron (Fe)?

1. (a) 50%
2. (b) 49%
3. (c) 46.15%
4. (d) 47.82%

Which is the correct order of degree of hydration among the following ions?

1. (a) Be²⁺ > Mg²⁺ > Sr²⁺ > Ba²⁺
2. (b) Be²⁺ > Sr²⁺ > Mg²⁺ > Ba²⁺
3. (c) Ba²⁺ > Sr²⁺ > Mg²⁺ > Be²⁺
4. (d) Ba²⁺ > Mg²⁺ > Sr²⁺ > Be²⁺

Consider the following statements regarding diagonal relationship of ‘B’ and ‘Si’:

1. The electronegativity values of both the elements are almost same
2. Both the elements have almost identical values of their ionic potential

Which of the statements given above is/are correct?

1. (a) 1 and 2
2. (b) 1 only
3. (c) 2 only
4. (d) Neither 1 nor 2

Consider the following statements regarding Lanthanum:

1. It is a f-block element
2. It is an inner transition element
3. It is a transition series element
4. It is a rare earth metal

Which of the statements given above are correct?

1. (a) 1, 2, 3 and 4
2. (b) 2 and 4 only
3. (c) 1, 2 and 4 only
4. (d) 1 and 3 only

Argon (Ar) is used in arc welding because of its:

1. (a) High calorific value
2. (b) Ability to lower the melting point of metal
3. (c) Low reactivity
4. (d) Flammability

Which one of the following represents the correct order of ionic radii among K⁺, S²⁻, Cl⁻ and Ca²⁺?

1. (a) Ca²⁺ > K⁺ > Cl⁻ > S²⁻
2. (b) S²⁻ > Cl⁻ > K⁺ > Ca²⁺
3. (c) Cl⁻ > S²⁻ > K⁺ > Ca²⁺
4. (d) K⁺ > Ca²⁺ > S²⁻ > Cl⁻

The dipole moments of H─C≡C─Cl, CO and HCl are in the directions:

1. (a) ←, ← and ← respectively
2. (b) ←, ← and → respectively
3. (c) →, → and → respectively
4. (d) ←, → and ← respectively

Consider the following pairs of species of oxygen and their magnetic behavior:

1. O₂⁻, O₂²⁻ → Both diamagnetic
2. O₂⁺, O₂²⁻ → Both paramagnetic
3. O₂⁺, O₂⁻ → Both paramagnetic
4. O, O₂²⁻ → Both paramagnetic

Which of the pair(s) of oxygen species given above represents the correct magnetic behavior?

1. (a) 1 only
2. (b) 1 and 2
3. (c) 3
4. (d) 2 and 4

Consider the following statements regarding the properties of Nitric oxide (NO):

1. Nitric oxide gas is paramagnetic but liquid nitric oxide is diamagnetic
2. Nitric oxide gas is diamagnetic but liquid nitric oxide is paramagnetic
3. Nitric oxide is a neutral oxide and is not an acid anhydride

Which of the statement(s) given above is/are correct?

1. (a) 1 and 3
2. (b) 1 only
3. (c) 2 and 3
4. (d) 2 only

Which one of the following substances has the greatest ionic character?

1. (a) Cl₂O
2. (b) NCl₃
3. (c) PbCl₂
4. (d) BaCl₂

Consider the following statements regarding Madelung constant:
Statement-1: Madelung constant typically increases with coordination number
Statement-2: Large contribution towards Madelung constant comes from nearest neighbors, and such neighbors are more numerous when coordination number is large

Which one of the following is correct in respect of above statements?

1. (a) Both statement-1 and statement-2 are true and statement-2 is the correct explanation of statement-1
2. (b) Both statement-1 and statement-2 are true but statement-2 is not the correct explanation of statement-1
3. (c) Statement-1 is true but statement-2 is false
4. (d) Statement-1 is false but statement-2 is true

Which one of the following represents the correct order of melting point among BeCl₂, MgCl₂, CaCl₂ and NaCl?

1. (a) BeCl₂ < MgCl₂ < CaCl₂ < NaCl
2. (b) MgCl₂ < BeCl₂ < CaCl₂ < NaCl
3. (c) BeCl₂ < MgCl₂ < NaCl < CaCl₂
4. (d) BeCl₂ < CaCl₂ < MgCl₂ < NaCl

What kind of defect(s) appear in AgBr crystal?

1. (a) Schottky and Frenkel
2. (b) Frenkel only
3. (c) Schottky only
4. (d) Metal excess defect

Consider the following statements:

1. N₂ molecule is paramagnetic
2. O₂ molecule is diamagnetic
3. CO⁺ has more bond order than CO
4. NO⁺ has less bond order than NO

Which of the statement(s) given above is/are correct?

1. (a) 1 and 4
2. (b) 1 and 2
3. (c) 3
4. (d) 2 only

The correct order of the bond angles among NH₃, NH₄⁺ and NH₂⁻ is:

1. (a) NH₃ > NH₄⁺ > NH₂⁻
2. (b) NH₄⁺ > NH₃ > NH₂⁻
3. (c) NH₃ > NH₂⁻ > NH₄⁺
4. (d) NH₄⁺ > NH₂⁻ > NH₃

Consider the following statements:
Statement-1: KO₂ is paramagnetic
Statement-2: The super oxide O₂⁻ is paramagnetic because it has one unpaired electron in π* 2p molecular orbital

Which one of the following is correct in respect of above statements?

1. (a) Both statement-1 and statement-2 are true and statement-2 is the correct explanation of statement-1
2. (b) Both statement-1 and statement-2 are true but statement-2 is not the correct explanation of statement-1
3. (c) Statement-1 is true but statement-2 is false
4. (d) Statement-1 is false but statement-2 is true

Which one of the following is NOT a resonance structure of cyanate (OCN⁻)?

1. (a) :Ö=C=N̈:⁻ (O two lone pairs, N two lone pairs, −1 on N)
2. (b) :Ö:⁻–C≡N: (O three lone pairs with −1, N one lone pair)
3. (c) :O⁺≡C–N̈:²⁻ (O one lone pair with +1, N three lone pairs with −2)
4. (d) :Ö=C=N:⁻ (O two lone pairs, N only one lone pair, −1 on N)

What are the spin only magnetic moments (in BM) for Ni (II) ion in a square planar and octahedral geometry, respectively?

1. (a) 0 (zero) and 2.83
2. (b) 2.83 and 0 (zero)
3. (c) 2.83 and 2.83
4. (d) 0 (zero) and 0 (zero)

Which one of the following complexes is tetrahedral as well as diamagnetic?

1. (a) [Ni(NH₃)₄]²⁺
2. (b) [NiCl₄]²⁻
3. (c) [Ni(CO)₄]
4. (d) [Ni(CN)₄]²⁻

Which one of the following will NOT precipitate AgCl while reacting with excess of AgNO₃ solution at room temperature?
(The oxidation state of cobalt (Co) in all the complexes is +3)

1. (a) CoCl₃.6NH₃
2. (b) CoCl₃.5NH₃
3. (c) CoCl₃.4NH₃
4. (d) CoCl₃.3NH₃

Which one of the following complexes CANNOT be ionized in solution?

1. (a) [Pt(NH₃)₆]Cl₄
2. (b) K₂[PtF₆]
3. (c) K₄[Fe(CN)₆]
4. (d) [Co(NH₃)₃Cl₃]

The maximum denticity of the polydentate ligand tetraethylene pentamine is equal to:

1. (a) 4
2. (b) 2
3. (c) 5
4. (d) 3

The correct IUPAC name of K₂[Zn(OH)₄] is:

1. (a) Dipotassium tetrahydroxo zinc (II)
2. (b) Potassium tetrahydroxo zinc (II)
3. (c) Potassium tetrahydroxido zincate (II)
4. (d) Dipotassium tetrahydroxido zincate (II)

Which one of the following octahedral complexes does NOT show geometrical isomerism?
(‘A’ and ‘B’ are monodentate ligands)

1. (a) [MA₂B₄]
2. (b) [MA₃B₃]
3. (c) [MA₄B₂]
4. (d) [MA₅B]

Which one of the following will NOT show optical isomerism?

1. (a) [Cr(C₂O₄)₃]³⁻
2. (b) Cis-[PtCl₂(en)₂]²⁺
3. (c) [Co(EDTA)]⁻
4. (d) [PtCl₂(NH₃)₂]

How many isomers are possible for [Co(en)₂Cl₂]⁺ complex ion?

1. (a) 1
2. (b) 2
3. (c) 3
4. (d) 4

Which one of the following equilibria will shift to the left in response to increase in pressure?

1. (a) N₂ + 3H₂ ⇋ 2NH₃ + 22.2 Kcal
2. (b) H₂ + I₂ + 12.4 Kcal ⇋ 2HI
3. (c) N₂ + O₂ ⇋ 2NO – 43.2 Kcal
4. (d) N₂O₄ + 14 Kcal ⇋ 2NO₂

The correct order of the acidic strength of H₃PO₄, H₃PO₃ and H₃PO₂ is:

1. (a) H₃PO₂ > H₃PO₃ > H₃PO₄
2. (b) H₃PO₄ > H₃PO₃ > H₃PO₂
3. (c) H₃PO₄ > H₃PO₂ > H₃PO₃
4. (d) H₃PO₃ > H₃PO₄ > H₃PO₂

Which one of the following substances has highest proton affinity?

1. (a) H₂O
2. (b) NH₃
3. (c) H₂S
4. (d) CH₃COOH

An aqueous solution of HN₃ was diluted two times, three times, four times and five times using required amount of water. Considering ‘α’ to be the ionization constant and ‘V’ as the final volume of diluted solution, choose the correct answer from the following:

1. (a) All the solutions will be acidic and the graph of α vs. V is non-linear
2. (b) All the solutions will be basic and the graph of α vs. V is non-linear
3. (c) All the solutions will be acidic and the graph of α vs. V is linear
4. (d) All the solutions will be basic and the graph of α vs. V is linear

Which one of the following represents the correct order of acidity of water and alcohols?

1. (a) H₂O > RCH₂OH > R₂CHOH > R₃COH
2. (b) RCH₂OH > R₂CHOH > R₃COH > H₂O
3. (c) H₂O < RCH₂OH < R₂CHOH < R₃COH
4. (d) RCH₂OH < R₂CHOH < R₃COH < H₂O

A student calculated the pH of 10⁻⁷ M NaOH solution and 10⁻⁸ M HCl solution to be 7 and 8, respectively. To verify, the student performed experiment in laboratory using pH-meter. The instrument displays the pH of former and later solutions as 7.3 and 6.9, respectively. Choose the correct answer from the following:

1. (a) The pH-meter is malfunctioned and the calculation results of the student are correct
2. (b) The pH-meter is working properly and the calculation results of the student are incorrect
3. (c) The pH-meter is malfunctioned and the calculation results of the student are wrong
4. (d) The calculation results of the student are correct and the instrument is working properly only for acids

Which one of the following has the pH value NOT equal to one?

1. (a) 0.1 M HNO₃
2. (b) 0.05 M H₂SO₄
3. (c) 0.1 M CH₃COOH
4. (d) 50 ml of 0.4 M HCl + 50 ml of 0.2 M NaOH

What will be the pH of a buffer solution containing 0.20 mole of NH₄OH and 0.25 mole of NH₄Cl per litre?
(Dissociation constant of NH₄OH at room temperature is 1.81 × 10⁻⁵, log1.81 = 0.2577 and log1.25 = 0.0969)

1. (a) 9.161
2. (b) 9.521
3. (c) 8.161
4. (d) 9.312

The molarity of concentrated commercial HCl with 36 % (w/w) HCl and density 1.19 g/cm³ is close to:

1. (a) 11.7 M
2. (b) 10.6 M
3. (c) 11.2 M
4. (d) 11.5 M

Which one of the following primary standard is usually used to standardize KOH by titration?

1. (a) Potassium acid phthalate
2. (b) Sulphuric acid
3. (c) Hydrochloric acid
4. (d) Nitric acid

While performing the titration between Mohr’s salt solution and potassium dichromate solution using diphenylamine as indicator, a student forgot to add o-phosphoric acid. Choose the correct answer from the following:

1. (a) The end point will be observed before the actual end point
2. (b) The end point will be observed after the actual end point
3. (c) The end point will never be observed
4. (d) The end point will be observed at its actual end point as there was no need to add o-phosphoric acid

Consider following statements in respect of titration between Ca²⁺ solution and EDTA solution using Eriochrome Black T as indicator (In):

1. The end point will be red in color
2. The end point will be blue in color
3. The end point depends on pH of solution which is controlled by adding ammonia –ammonium citrate buffer
4. The end point is observed since metal–In complex is more stable than metal–EDTA complex

Which of the statement(s) given above is/are correct?

1. (a) 1, 3 and 4
2. (b) 2, 3 and 4
3. (c) 2 and 3 only
4. (d) 2 only

In acid base titration the color change of an indicator is expressed by:
\(pH = pK'_{In} + \log\frac{[In_B]}{[In_A]}\)
(Where \(In_B\) = Indicator in the basic form, \(In_A\) = indicator in acid form)
The basic color of the indicator would be visible when:

1. (a) \([In_B]/[In_A] > 10\)
2. (b) \([In_B]/[In_A] < 10\)
3. (c) \([In_A]/[In_B] > 10\)
4. (d) \([In_B] = [In_A]\)

Which one of the following comparisons of the average translational kinetic energy (K.E.) and the average molecular speeds of H₂ and N₂ gases at 300 K is correct?

1. (a) Average translational K.E.: H₂ = N₂; Average molecular speed: H₂ = N₂
2. (b) Average translational K.E.: H₂ < N₂; Average molecular speed: H₂ > N₂
3. (c) Average translational K.E.: H₂ = N₂; Average molecular speed: H₂ < N₂
4. (d) Average translational K.E.: H₂ = N₂; Average molecular speed: H₂ > N₂

The expression of isothermal compressibility factor is:

1. (a) \(K_T = \frac{1}{V}\left(\frac{\partial V}{\partial P}\right)_T\)
2. (b) \(K_T = -\frac{1}{V}\left(\frac{\partial V}{\partial P}\right)_T\)
3. (c) \(K_T = \frac{1}{V}\left(\frac{\partial V}{\partial T}\right)_P\)
4. (d) \(K_T = -\frac{1}{V}\left(\frac{\partial V}{\partial T}\right)_P\)

An equimolar mixture of H₂ and N₂ is allowed to effuse through a hole. What is the ratio of rate of diffusion of H₂ to that of N₂?
(M.W. of H₂ = 2 g mol⁻¹ and M.W. of N₂ = 28 g mol⁻¹)

1. (a) 1 : 3.7
2. (b) 3.7 : 1
3. (c) 1 : 14
4. (d) 14 : 1

The temperature at which the average velocity of Nitrogen (N₂) is equal to that of Oxygen (O₂) at 320 K is:
(M.W. of N₂ = 28 g mol⁻¹ and M.W. of O₂ = 32 g mol⁻¹)

1. (a) 365.68 K
2. (b) 280 K
3. (c) 225 K
4. (d) 300 K

Which one of the following relations for three types of velocities is true for oxygen gas at 300 K?
(where ⟨c²⟩^½ = root mean square velocity; ⟨c⟩ = average velocity; c_p = most probable velocity)

1. (a) ⟨c²⟩^½ > c_p > ⟨c⟩
2. (b) ⟨c⟩ > c_p > ⟨c²⟩^½
3. (c) ⟨c²⟩^½ > ⟨c⟩ > c_p
4. (d) ⟨c⟩ > ⟨c²⟩^½ > c_p

Consider the following statements regarding the most probable speed of gas particles:

1. The most probable speed increases with increasing temperature and with decreasing molar mass and simultaneously distribution becomes broader
2. The most probable speed increases with increasing temperature and with increasing molar mass and distribution becomes sharp
3. The most probable speed decreases with the decrease of temperature and with increasing molar mass and simultaneously distribution becomes sharp

Which of the statement(s) given above is/are correct?

1. (a) 1 and 3
2. (b) 2 and 3
3. (c) 1 only
4. (d) 2 only

One hundred molecules of Oxygen (O₂) escape through a small hole on a container at a pressure of 1 torr and temperature of 300 K per second to vacuum. The number of hydrogen molecules that would escape per second through the same hole under the same conditions of temperature and pressure is:
(M.W. of O₂ = 32 g mol⁻¹ and M.W. of H₂ = 2 g mol⁻¹)

1. (a) 1200
2. (b) 800
3. (c) 1600
4. (d) 400

The mean free path of a gas is:

1. (a) Independent of temperature but dependent on pressure
2. (b) Independent of pressure but dependent on temperature
3. (c) Independent of both pressure and temperature
4. (d) Dependent on both pressure and temperature

Which one of the following is NOT a Maxwell thermodynamic relation?

1. (a) \(\left(\frac{\partial S}{\partial V}\right)_T = \left(\frac{\partial P}{\partial T}\right)_V\)
2. (b) \(\left(\frac{\partial S}{\partial P}\right)_T = \left(\frac{\partial V}{\partial T}\right)_P\)
3. (c) \(\left(\frac{\partial V}{\partial S}\right)_P = \left(\frac{\partial T}{\partial P}\right)_S\)
4. (d) \(-\left(\frac{\partial P}{\partial S}\right)_V = \left(\frac{\partial T}{\partial V}\right)_S\)

Consider the following first order elementary reaction:
The half-life period of the forward reaction is 10 min. and that of the backward reaction is 1 min. What is the value of equilibrium constant for the above reaction?

1. (a) 0.693
2. (b) 0.0693
3. (c) 0.10
4. (d) 10.0

Consider the following figure representing the increase in entropy of a substance from absolute zero to its gaseous state with temperature change:

ΔS° (fusion) and ΔS° (vaporization) are respectively indicated by:

1. (a) AB and BC
2. (b) BC and CD
3. (c) BC and DE
4. (d) CD and DE

Consider the following quantities:

1. Concentration
2. Volume
3. Standard electrode potential
4. Internal energy

Which of the following statements given below are correct?

1. (a) 1 and 3 are intensive quantities; 2 and 4 are extensive quantities
2. (b) 1 and 4 are extensive quantities; 2 and 3 are intensive quantities
3. (c) 1 and 2 are extensive quantities; 3 and 4 are intensive quantities
4. (d) 1, 2 and 4 are extensive quantities; 3 is intensive quantity

Joule Thomson coefficient for a gas is given by:

1. (a) \(\mu_{JT} = -C_P\left(\frac{\partial H}{\partial P}\right)_T\)
2. (b) \(\mu_{JT} = -\left(\frac{\partial H}{\partial P}\right)_T\)
3. (c) \(\mu_{JT} = -\frac{1}{C_P}\left(\frac{\partial H}{\partial P}\right)_T\)
4. (d) \(\mu_{JT} = \frac{1}{C_P}\left(\frac{\partial H}{\partial P}\right)_T\)

Consider the following statements regarding Joule Thomson effect:

1. Joule Thomson effect occurs at constant enthalpy
2. For perfect gas Joule Thomson coefficient is zero
3. Heating effect corresponds to positive value of Joule Thomson coefficient

Which of the statements given above is/are correct?

1. (a) 1 and 3
2. (b) 1 and 2
3. (c) 2 and 3
4. (d) 3 only

For the reaction H₂F₂(g) → H₂(g) + F₂(g), ΔH is equal to:

1. (a) ΔE + 2RT
2. (b) ΔE – 2RT
3. (c) ΔE
4. (d) ΔE + RT

Which of the following thermodynamic relations are correct?

1. \(\lim_{T \to 0} S = 0\)
2. \(S_T = \int_0^T \frac{C_P\,dT}{T}\)
3. \(-\Delta S = \left(\frac{\partial(\Delta G)}{\partial T}\right)_P\)

Select the correct answer using the code given below:

1. (a) 1 and 2 only
2. (b) 1 and 3 only
3. (c) 2 and 3 only
4. (d) 1, 2 and 3

What is the sign of ΔG° and the value of K for an electrochemical cell for which E°cell = 0.80V?

1. (a) ΔG° is negative and K >1
2. (b) ΔG° is positive and K>1
3. (c) ΔG° is positive and K<1
4. (d) ΔG° is negative and K<1

If ΔG = ΔH – TΔS and \(\Delta G = \Delta H + T\left(\frac{\delta(\Delta G)}{\delta T}\right)_P\) then the variation of emf of cell (E°) with temperature T at constant pressure is given by:

1. (a) \(\frac{\Delta H}{nF}\)
2. (b) \(\frac{\Delta G}{nF}\)
3. (c) \(\frac{\Delta S}{nF}\)
4. (d) \(-\frac{\Delta S}{nF}\)

Which of the following is correct about the sign of enthalpy and entropy changes of an evaporating liquid?

1. (a) ΔH is positive; ΔS is positive
2. (b) ΔH is negative; ΔS is negative
3. (c) ΔH is positive; ΔS is negative
4. (d) ΔH is negative; ΔS is positive

Consider the following equilibrium process at 373K and 1 atm. pressure:
Which one of the following relations is true for the above process?

1. (a) ΔH = 0
2. (b) ΔE = 0
3. (c) ΔH = TΔS
4. (d) ΔH = ΔE

Which one of the following aqueous solutions has the lowest vapor pressure at room temperature?

1. (a) 0.1 molal hexaamminecobalt (III) chloride
2. (b) 0.1 molal barium chloride
3. (c) 0.1 molal glucose
4. (d) 0.1 molal Tris (ethylenediamine) copper (II) sulfate

Compared to pure water, 1 M sugar-water solution will have a:

1. (a) Lower vapor pressure, lower boiling point and lower freezing point
2. (b) Lower vapor pressure, lower boiling point and higher freezing point
3. (c) Lower vapor pressure, higher boiling point and lower freezing point
4. (d) Higher vapor pressure, higher boiling point and higher freezing point

The relation between osmotic pressure (Π) and lowering of vapor pressure in an infinitely dilute solution is:

1. (a) \(\Pi = V^0 RT \ln\left(\frac{p}{p^0}\right)\)
2. (b) \(\Pi = \frac{RT}{V^0} \ln\left(\frac{p^0}{p}\right)\)
3. (c) \(\Pi = V^0 + RT \ln\left(\frac{p}{p^0}\right)\)
4. (d) \(\Pi = V^0 - RT \ln\left(\frac{p}{p^0}\right)\)

The vapor pressure of ethyl acetate at 293K is 72.8 torr. The vapor pressure of the solution obtained by dissolving 0.4 g of a non-volatile solute (molar mass = 60 gmol⁻¹) in 100 g of ethyl acetate at the same temperature is:

1. (a) 72.91 torr
2. (b) 72.37 torr
3. (c) 72.60 torr
4. (d) 72.00 torr

People with high blood pressure are advised to have lower intake of salt in their food because:

1. Higher intake of salt causes higher osmotic pressure
2. It results in greater inflow of water in the cells and causes water retention in the tissue cells and intercellular spaces

Which of the statement(s) given above is/are correct?

1. (a) 1 only
2. (b) 2 only
3. (c) 1 and 2
4. (d) Neither 1 nor 2

The equation Π = c₂RT is known as:
(where c₂ = n₂/V is the molar concentration of the solute in the given solution and other symbols have their usual meanings)

1. (a) Van’t Hoff equation
2. (b) Raoult’s law equation
3. (c) Henry law equation
4. (d) Walden’s rule

The boiling point of Chloroform was raised by 0.325K when 5.141 × 10⁻⁴ kg of a non-volatile solute was dissolved in 35 × 10⁻³ kg of Chloroform. Calculate the molar mass of the solute?
(molal boiling point elevation constant for chloroform is 3.9 K kg mol⁻¹)

1. (a) 0.215 kg mol⁻¹
2. (b) 0.176 kg mol⁻¹
3. (c) 0.195 kg mol⁻¹
4. (d) 0.151 kg mol⁻¹

P is the total vapor pressure of an ideal binary liquid solution. If y_A and y_B are the amount fractions of the constituents in vapor phase, then which one of the following statements is correct?

1. (a) P varies linearly with y_A and y_B
2. (b) 1/P varies linearly with y_A and y_B
3. (c) P varies linearly with y_A and y_B and passes through origin
4. (d) 1/P varies linearly with y_A and y_B and passes through origin

The Henry Law constant (Kᵢ) for Hydrogen (H₂) in water at room temperature is 7.03 × 10⁹ Pa. If the pressure of H₂ in equilibrium with water is 1.00 × 10⁶ Pa at the same temperature, then the mole fraction of H₂ in the solution is:

1. (a) 0.00427
2. (b) 0.0427
3. (c) 0.000821
4. (d) 0.000142

Specific conductance of a decimolar solution of KCl at 18 °C is 1.12 Sm⁻¹. The resistance of a conductivity cell containing the solution at the same temperature was found to be 55 ohm. What is the cell constant?

1. (a) 0.616 cm⁻¹
2. (b) 0.716 cm⁻¹
3. (c) 0.516 cm⁻¹
4. (d) 0.699 cm⁻¹

In acidic medium MnO₄⁻ converted to Mn²⁺. The quantity of electricity in Faraday required to reduce 0.2 mole of MnO₄⁻ to Mn²⁺ would be:

1. (a) 0.2
2. (b) 0.4
3. (c) 1
4. (d) 2.5

What will be the correct order of mobility of the following ions in aqueous solution at 298 K?

1. (a) Cl⁻ > F⁻ > SO₄²⁻ > Br⁻
2. (b) F⁻ > SO₄²⁻ > Br⁻ > Cl⁻
3. (c) SO₄²⁻ > Br⁻ > Cl⁻ > F⁻
4. (d) Br⁻ > SO₄²⁻ > Cl⁻ > F⁻

At 291 K the ionic velocities of Ag⁺ is 0.00057 cm/s and that of NO₃⁻ is 0.00063 cm/s. If the specific conductivity of 0.1N AgNO₃ solution is 0.00947ohm⁻¹cm⁻¹, then the degree of dissociation at this dilution is:

1. (a) 0.817
2. (b) 0.918
3. (c) 0.698
4. (d) 0.761

Plots of equivalent conductance (∧) vs square root of concentration (√C) of two electrolytes are given below, with ∧₀ being the equivalent conductance at infinite dilution:

Which one of the following statements is correct?

1. (a) Plot I is for weak electrolyte and plot II is for strong electrolyte
2. (b) Extrapolation to ∧₀ as shown in plot I cannot be done
3. (c) Extrapolation to ∧₀ in plot II cannot be done to get the correct ∧₀
4. (d) Plots I and II are valid for any electrolyte for different range of concentrations

Consider the following statements for an electrolyte solution which is diluted to approach infinite dilution:
Statement-I: Ion-ion interactions are reduced to effect the increase in conductance
Statement-II: The number of ions gets increased to effect increase in conductance

Which one of the following is correct with respect to above statements?

1. (a) Both the statements I and II are true for strong electrolytes
2. (b) Both the statements I and II are true for weak electrolytes
3. (c) Statement I is true for weak electrolytes and statement II is true for strong electrolytes
4. (d) Statement I is true for strong electrolytes and statement II is true for weak electrolytes

The value of log γ± in the Debye-Huckel limiting law for a 0.01m KCl solution in water at 25 °C is:
(where γ± is the mean ionic activity coefficient)

1. (a) – 0.1018
2. (b) – 0.0509
3. (c) + 0.1018
4. (d) – 0.0254

Consider the following plot:

The above plot indicates the conductometric titration between:

1. (a) Weak acid vs weak base
2. (b) Strong acid vs weak base
3. (c) Weak acid vs strong base
4. (d) Strong acid vs strong base

Consider the following plot for conductometric study of a reaction between KCl and AgNO₃ solutions:

Cause/s behind the constancy of conductance in the region PQ is/are due to:

1. (a) Precipitation of AgCl only
2. (b) Replacement of Cl⁻ by NO₃⁻ with each species having equal conductance
3. (c) Precipitation of AgCl and replacement of Cl⁻ by NO₃⁻
4. (d) Inert behavior of the instrument in this region

Consider the following plot for the conductometric titration:

Which one of the following is correct in respect of above plot?

1. (a) Plot I is for weak acid vs weak alkali; plot II is for weak acid vs strong alkali
2. (b) Plot I is for strong acid vs strong alkali; plot II is for AgNO₃ solution vs NH₄Cl solution
3. (c) Plot I is for AgNO₃ solution vs HCl; plot II is for AgNO₃ vs KCl
4. (d) Plot I is for weak acid vs strong alkali; plot II is for weak acid vs weak alkali

Two electrolytes AX and BX were chosen to determine transport number using moving boundary method. It is given that:
I: The cation B⁺ moves slower than the cation A⁺
II: The electrolyte BX is denser than AX
Which one of the following is correct?

1. (a) The transport number of A⁺ can be determined if AX is used as principal electrolyte and BX as indicator electrolyte
2. (b) The transport number of B⁺ can be determined if AX is used as indicator electrolyte and BX as principal electrolyte
3. (c) The transport number of X⁻ can be determined if AX is used as indicator electrolyte and BX as principal electrolyte
4. (d) The transport number of A⁺, B⁺ and X⁻ can be determined if AX is used as principal electrolyte and BX as indicator electrolyte

The total number of delocalized pi-electrons in compounds I and II are:

1. (a) 18 and 14 respectively
2. (b) 24 and 16 respectively
3. (c) 16 and 12 respectively
4. (d) 22 and 14 respectively

Rank the following structures in order of increasing contribution to the resonance hybrid:

1. (a) II < I < III
2. (b) III < II < I
3. (c) III < I < II
4. (d) I < II < III

Which of the following indicated atoms in each species has sp²-hybridization?

1. (a) I and III only
2. (b) I, III and IV only
3. (c) II and IV only
4. (d) I, II, III and IV

The total number of hyperconjugative structures possible for the following carbocation is:

1. (a) 3
2. (b) 1
3. (c) 4
4. (d) 12

Which one of the following statements regarding polarity of bonds is NOT true?

1. (a) A compound with only one polar bond must be polar
2. (b) A compound with two or more polar bonds will always be polar
3. (c) A compound cannot be polar if it contains only nonpolar bonds
4. (d) More electronegative atoms “pull” electron density towards them, making a dipole

The correct order of the basicity of the following amines is:

1. (a) IV > III > II > I
2. (b) III > IV > I > II
3. (c) IV > III > I > II
4. (d) III > IV > II > I

The correct order of stability of the following carbocations is:

1. (a) II > IV > I > III
2. (b) I > II > III > IV
3. (c) II > I > IV > III
4. (d) I > III > II > IV

Rank the following compounds in order of their decreasing dipole moment:

1. (a) III > II > IV > I
2. (b) IV > III > I > II
3. (c) II > IV > III > I
4. (d) I > II > IV > III

The relationship between the following pair of compounds is:

1. (a) Identical
2. (b) Enantiomers
3. (c) Diastereomers
4. (d) Constitutional isomers

Consider the following set of compounds:

Which one of the following statements is NOT true about the above compounds (I–IV)?

1. (a) I and II represent same structures and are meso compounds
2. (b) [I and III] and [I and IV] are diastereomers
3. (c) III and IV are enantiomers
4. (d) III and IV are diastereomers

The correct statement about the following molecule is:

1. (a) Molecule is chiral and possesses a chiral plane
2. (b) Molecule is chiral and possesses a chiral axis
3. (c) Molecule is achiral and possesses a plane of symmetry
4. (d) Molecule is achiral and possesses a centre of symmetry

A sample of lactic acid was found to have an enantiomeric excess (ee) of 14% with respect to R (+) isomer. What is the percentage of S (–) isomer in the sample?

1. (a) 86
2. (b) 57
3. (c) 43
4. (d) 72

In 2-butanol observed angle of rotation is 1.03°, concentration of sample is 1M and length of sample tube is 10 cm. Specific angle of rotation will be:

1. (a) 1.392°
2. (b) 13.92°
3. (c) 14.20°
4. (d) 139.2°

The absolute configuration of C2 and C3 in the following compound is:

1. (a) 2R, 3S
2. (b) 2S, 3R
3. (c) 2S, 3S
4. (d) 2R, 3R

The configuration of C1 and C2 carbons in the following molecule is:

1. (a) 1S, 2R
2. (b) 1R, 2R
3. (c) 1R, 2S
4. (d) 1S, 2S

The most stable conformation of the following compound is:

1. (a) Chair with t-Bu equatorial and both Me equatorial
2. (b) Chair with t-Bu equatorial, Me on the far ring carbon axial (up) and Me on the adjacent carbon equatorial
3. (c) Chair with t-Bu equatorial and both Me axial (one up, one down)
4. (d) Chair with t-Bu equatorial, Me on the far ring carbon equatorial and Me on the adjacent carbon axial (down)

The stereochemical notations for the following compound is:

1. (a) 2E, 4E, 6S
2. (b) 2Z, 4E, 6S
3. (c) 2Z, 4E, 6R
4. (d) 2Z, 4Z, 6R

The total number of geometrical isomers for the following compound is:

1. (a) 4
2. (b) 5
3. (c) 6
4. (d) 7

The correct order of stability of Newman projections of 1, 2-dichloroethane is:

1. (a) anti > eclipsed > gauche
2. (b) gauche > eclipsed > anti
3. (c) gauche > anti > eclipsed
4. (d) anti > gauche > eclipsed

Among the following, the Newman projections for meso-2,3-butanediol are:

1. (a) I and II
2. (b) I and III
3. (c) III and IV
4. (d) II and IV

The major products [X] and [Y] formed in the following reactions are:

1. (a) [X] = trans-2-butene and [Y] = cis-2-butene
2. (b) [X] = cis-2-butene and [Y] = trans-2-butene
3. (c) [X] = [Y] = cis-2-butene
4. (d) [X] = [Y] = trans-2-butene

Which one of the following chlorides undergoes a fastest SN2 reaction with KI in acetone?

1. (a) PhCOCH₂Cl (phenacyl chloride)
2. (b) PhCH₂Cl (benzyl chloride)
3. (c) CH₂=CHCH₂Cl (allyl chloride)
4. (d) CH₃OCH₂Cl (chloromethyl methyl ether)

Indicate the order of reactivity of HX in the following reaction:

1. (a) HI > HBr > HCl
2. (b) HCl > HBr > HI
3. (c) HBr > HI > HCl
4. (d) HBr > HCl > HI

Which isomer of 1,2,3,4,5,6-hexachlorocyclohexane shown below undergoes E2 elimination (dehydrohalogenation) most slowly?

1. (a) Cl wedge/wedge/wedge/hash/wedge/hash around the ring
2. (b) All six Cl on wedges (all-cis)
3. (c) Cl alternating wedge/hash around the ring (all-trans, β-isomer)
4. (d) Three adjacent Cl on wedges and three adjacent on hashes

The following reaction is an example of:

1. (a) E2 elimination
2. (b) E1 elimination
3. (c) E1cb elimination
4. (d) Syn elimination

Which of the following statement is TRUE for the reaction mentioned below?

1. (a) I is major and it is called Hoffmann product
2. (b) I is minor and it is called Zaitsev product
3. (c) II is major and it is called Zaitsev product
4. (d) II is minor and it is called Hoffmann product

Which one of the following alcohols dehydrates the fastest when heated with acid?

1. (a) 2-Methylcyclohexanol
2. (b) 1-Methylcyclohexanol
3. (c) Cyclohexylmethanol
4. (d) 1-Methylcyclohex-2-en-1-ol

The major product formed in the following reaction is:

1. (a) trans-3-bromo-2-methoxytetrahydropyran (Br wedge, OMe hash)
2. (b) trans-2-bromo-3-methoxytetrahydropyran
3. (c) cis-2,3-dibromotetrahydropyran
4. (d) trans-2,3-dimethoxytetrahydropyran

Which one of the following alkenes will react most rapidly with concentrated sulphuric acid?

1. (a) H₂C=CH₂
2. (b) (CH₃)₂C=CH₂
3. (c) Cl₂C=CCl₂
4. (d) F₃CCH=CHCH₃

The regioselective electrophilic addition of HOCl with propene proceeds through:

1. (a) \(CH_3-\overset{+}{C}H-CH_2Cl\)
2. (b) \(CH_3-\overset{+}{C}H-CH_2OH\)
3. (c) CH₃–CH(OH)–CH₂⁺
4. (d) CH₃–CH(Cl)–CH₂⁺

Which one of the following products is formed when bromine adds to anthracene?

1. (a) 1,4-Dibromo-1,4-dihydroanthracene
2. (b) 1,2-Dibromo-1,2-dihydroanthracene
3. (c) 2,3-Dibromo-1,2,3,4-tetrahydroanthracene
4. (d) 9,10-Dibromo-9,10-dihydroanthracene

The correct sequence of reactions to accomplish the following transformation is:

1. (a) (i) CH₃CH₂Cl/AlCl₃, (ii) Cl₂/FeCl₃
2. (b) (i) Cl₂/FeCl₃, (ii) CH₃CH₂Cl/AlCl₃
3. (c) (i) CH₃COCl/AlCl₃, (ii) Cl₂/FeCl₃, (iii) Zn-Hg/HCl
4. (d) (i) CH₃COCl/AlCl₃, (ii) Zn-Hg/HCl, (iii) Cl₂/FeCl₃

The intermediate [X] and the major product [Y] formed in the following reaction are:

1. (a) [X] is carbocation and [Y] is 2-(3-methylpent-1-en-3-yl)benzoic acid
2. (b) [X] is carbanion and [Y] is 2-(3-methylpent-1-en-3-yl)aniline
3. (c) [X] is free radical and [Y] is (3-methylpent-1-en-3-yl)benzene
4. (d) [X] is benzyne and [Y] is 2-ethyl-1,4-dihydronaphthalene

Which is the major product formed in the reaction of phenol with bromine in carbon disulfide at 0–5°C temperature?

1. (a) 4-Bromophenyl hypobromite (p-BrC₆H₄OBr)
2. (b) 4-Bromophenol
3. (c) 2,4,6-Tribromophenol
4. (d) 2-Bromophenol

Which is the major product formed in the reaction of o-chloroanisole with NaNH₂ in liquid ammonia at low temperature?

1. (a) o-Anisidine
2. (b) m-Anisidine
3. (c) p-Anisidine
4. (d) o-chloroaniline

Predict the major product formed in the following reaction:

1. (a) (CH₃)₂C(Cl)–CH(CH₃)₂ (2-chloro-2,3-dimethylbutane)
2. (b) (CH₃)₃C–CH(Cl)–CH₃ (3-chloro-2,2-dimethylbutane)
3. (c) (CH₃)₃C–CH₂–CH₂Cl (1-chloro-3,3-dimethylbutane)
4. (d) (CH₃)₃C–CH(Cl)–CH₂Cl (1,2-dichloro-3,3-dimethylbutane)

Consider the following reaction:
The major product ‘P’ of Wagner-Meerwein rearrangement is:

1. (a) Chloride that keeps the bridged cyclobutane (pinane-type) skeleton, Cl on the bridge carbon next to the gem-dimethyl carbon
2. (b) Bornyl chloride (2-chloro-1,7,7-trimethylbicyclo[2.2.1]heptane)
3. (c) Chloride that keeps the pinane skeleton, Cl on the ring carbon next to the methyl-bearing carbon
4. (d) Bicyclo[2.2.1]heptyl chloride with a bridgehead methyl and Cl on a methyl-bearing (tertiary) ring carbon, unsubstituted C7 bridge

The major product formed in the following reaction is:

1. (a) Cyclohex-2-en-1-yl acetate
2. (b) Cyclohex-1-en-1-yl acetate
3. (c) trans-1,2-Diacetoxycyclohexane
4. (d) cis-1,2-Diacetoxycyclohexane

Which one of the following is NOT a characteristic of neighboring group participation effect?

1. (a) An unusual stereochemical result
2. (b) An unexpectedly fast rate of reaction
3. (c) Formation of a rearranged product
4. (d) The extent of neighboring group participation increases with increasing the nucleophilicity of nucleophile in solvolysis reaction

In which of the following solvents the neighboring group rate enhancement by phenyl group in the solvolysis of PhCH₂CH₂OTs is maximum?

1. (a) EtOH
2. (b) HCOOH
3. (c) CF₃COOH
4. (d) CH₃COOH