Question

The graphical variation of molar conductivity \((\Lambda )\) against square root of molar concentration \((\sqrt{c})\) of certain electrolyte 'X' is linear with intercept on y axis. Identify X from following.

• A. \(\text{CH}_3\text{COOH}\)
• B. \(\text{NH}_4\text{OH}\)
• C. \(\text{HCOOH}\)
• D. \(\text{CH}_3\text{COONa}\)

Hint:

Only strong electrolytes give a straight line with a finite intercept on the molar conductivity axis.

Answer 1

The Correct Option is D

Step 1: Shape of the graph:
A line with a clear intercept on the y axis means $\Lambda_m^0$ can be read directly. This is the Kohlrausch behaviour of strong electrolytes.

Step 2: Pick the electrolyte:
Acetic acid, ammonium hydroxide and formic acid are weak, so their graphs are curves that shoot upward near zero concentration. Sodium acetate is fully ionised in water, so it matches the straight line. Answer: (D).

Final Answer:
Sodium acetate. \[ \boxed{\text{(D)}} \]