The variation of molar conductivity with concentration of an electrolyte (X) in aqueous solution is shown in the given figure.
The electrolyte X is :

Solution

Chemistry ma’am · 3 steps

Look at the shape: a curve that shoots up only near zero concentration belongs to a weak electrolyte.

1. Strong electrolytes. A strong electrolyte is almost fully ionised at every concentration. Its molar conductivity falls only slightly as √c grows, giving a nearly straight line, Λₘ = Λₘ° - A√c.
2. Weak electrolytes. A weak electrolyte ionises only a little, and its degree of dissociation rises sharply on dilution. So Λₘ stays low over most of the range, then rises steeply as c approaches zero. That is the curve in the figure.

   Electrolyte	Type	Λₘ vs √c
   HCl	strong acid	nearly straight line
   CH₃COOH	weak acid	steep rise only near c = 0
   NaCl	strong salt	nearly straight line
   KNO₃	strong salt	nearly straight line

3. So. The graph matches a weak electrolyte, so X is acetic acid, CH₃COOH, option (b).

The idea to keep. In a Λₘ vs √c plot, a gentle straight line means a strong electrolyte. A steep climb near zero concentration means a weak one, whose Λₘ° cannot be found by extrapolation.

Answer from the NTA final answer key. Solution by PrepWiser.