Questions-block / solubility
Consider the following statements in respect of alkali metal halides:
- The low solubility of LiF in water is due to its high lattice enthalpy
- The low solubility of CsI in water is due to smaller hydration enthalpy of its two ions
Which of the statements given above is/are correct?
- (a) 1 only
- (b) 2 only
- (c) Both 1 and 2
- (d) Neither 1 nor 2
Answer: (c) Both 1 and 2
Solubility depends on lattice enthalpy vs hydration enthalpy. 1 ✔ LiF: tiny Li⁺ and F⁻ → very high lattice enthalpy → poorly soluble. 2 ✔ CsI: both ions large → low hydration enthalpy → poorly soluble. Both → (c).