UPSC Combined Geo-Scientist, Mains · 2021 · Mains Paper II
Q15(c). Why saturated KCl or NH₄NO₃ in a salt bridge
Question
Why is a saturated solution of KCl or NH₄NO₃ used in the salt bridge?
Answer in brief
Their cation and anion move at almost the same speed (t₊ ≈ t₋ ≈ 0.5), so the liquid junction potential is nearly zero; a saturated bridge makes these ions carry almost all the current.
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Coverssalt bridgeliquid junction potentialtransport numberKClionic mobility
All parts of Question 15
- 15(a) The J = 6 → 7 line from the J = 3 → 4 line of a rigid rotor10 marks
- 15(b) Normal modes of CS₂ and OCS; IR activity5 marks
- 15(c) Why saturated KCl or NH₄NO₃ in a salt bridge5 marks