JEE Main · 2020 · 03 Sep 2020 · Shift 1 · Redox Reactions and Electrochemistry

Let

C_{NaCl}

and

C_{BaSO_{4}}

be the conductances (in S ) measured for saturated aqueous solution of NaCl and

BaSO_{4}

, respectively, at a temperature T .

Which of the following is false?

(A) $C_{NaCl} (T_{2}) > C_{NaCl} (T_{1})$ for $T_{2} > T_{1}$
(B) $C_{NaCl} ≫ C_{BaSO_{4}}$ at a given T
(C) $C_{BaSO_{4}} (T_{2}) > C_{BaSO_{4}} (T_{1})$ for $T_{2} > T_{1}$
(D)Ionic mobilities of ions from both salts increase with T✓ Correct

Answer: (D)

Solution

Raising the temperature and dissolving more ions both raise conductance, so for the freely soluble

NaCl

and for the sparingly soluble

BaS O_{4}

the conductance of each saturated solution does rise as

T

increases, and at any one temperature the far more soluble

NaCl

solution conducts very much better than the

BaS O_{4}

solution; those three statements are sound. The remaining statement, which pins the behaviour on a common increase in the ionic mobilities of the ions from both salts, is the one that does not hold, since the rise in conductance of these saturated solutions is governed chiefly by how much salt goes into solution rather than by such a blanket mobility claim. It is therefore the false statement.

JEE Main · 2020 · 03 Sep 2020 · Shift 1 · Single correct option

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JEE Main · 2020 · 03 Sep 2020 · Shift 1 · Redox Reactions and Electrochemistry

Solution

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