Question

Which from following options is true when an electrolyte solution is diluted ?

• A. both \(\Lambda\) and \(k\) increases
• B. both \(\Lambda\) and \(k\) decreases
• C. \(\Lambda\) increases and \(k\) decreases
• D. \(\Lambda\) decreases and \(k\) increases

Hint:

On dilution, molar conductivity rises but conductivity falls.

Answer 1

The Correct Option is C

Step 1: Think of a physical picture:
Conductivity depends on how many ions sit in 1 cm$^3$. Adding water spreads the same ions over a bigger volume, so $k$ falls.

Step 2: Think of per-mole behaviour:
Molar conductivity measures conduction per mole of electrolyte. On dilution, inter-ionic attractions weaken and (for weak electrolytes) more molecules ionise, so each mole conducts better.

Step 3: Pick:
$\Lambda$ increases and $k$ decreases, which is option C.

Final Answer:
More dilution means a lower k but a higher molar conductivity. \[ \boxed{\text{(C) }\Lambda\ \text{increases and}\ k\ \text{decreases}} \]