Choose the correct representation of conductometric titration of benzoic acid vs sodium hydroxide.

Step 1 — Analyse the conductometric titration of benzoic acid (weak acid) vs NaOH (strong base):

Reaction: $\mathrm{C_6H_5COOH + NaOH \rightarrow C_6H_5COONa + H_2O}$

Step 2 — Conductance changes:

• Before equivalence point: As NaOH is added, highly mobile $\mathrm{H^+}$ ions (from partial dissociation of benzoic acid) are replaced by less mobile $\mathrm{Na^+}$ ions and $\mathrm{C_6H_5COO^-}$ ions. The benzoate buffer forms. Conductance decreases (replacement of $\mathrm{H^+}$ by less mobile ions).

• At equivalence point: Only $\mathrm{C_6H_5COONa}$ in solution → minimum conductance

• After equivalence point: Excess NaOH adds highly mobile $\mathrm{OH^-}$ ions → conductance increases sharply

Step 3 — Shape of graph: The graph shows a V-shape: decreasing conductance before equivalence point, minimum at equivalence point, then sharp increase after.

Answer: Option (2)