Question

Choose the correct option(s) when conductometric titration of a strong acid vs. weak base (titrant) is carried out:

• A. Conductance increases up to the equivalence point.
• B. Conductance decreases up to the equivalence point.
• C. Beyond equivalence point , conduction starts decreasing sharply.
• D. Beyond equivalence point , conduction remains almost constant.

Answer 1

Answer: (B), (D)

Beyond equivalence point , conduction remains almost constant.

Conductometric titration of strong acid vs. weak base
Example:
Titration of $HClwithN{H}_{4}OH$
On addition of $N{H}_{4}OH$ , highly mobile $H3O^{+}$ ions are replaced by weakly ionized $N{H}_4^{+}$ ions. Hence, conductance decreases up to the equivalence point.
Addition of $N{H}_{4}OH$ beyond equivalence point:
The conductance remains practically constant,due to increase in number of only $N{H}_{4}OH$ ions. $N{H}_{4}OH$ has very low conductance compared to $HCl$ or $N{H}_{4}Cl$