Question

Acetic acid is titrated with $NaOH$ solution. Which of the following statements is correct for this titration?

• A. Conductance slowly decreases upto the equivalence point, then it decreases rapidly
• B. Conductance decreases upto equivalence point, then it increases
• C. First conductance increases slowly up to the equivalence point and then increases rapidly
• D. First conductance increases slowly up to the equivalence point and then drops rapidly

Answer 1

The correct option is C First conductance increases slowly up to the equivalence point and then increases rapidly

Before titration, low initial conductance is observed due to low $H^{+}$ ion obtained during dissociation of weak $C{H}_{3}COOH$ acid . Then during titration, slight decrease of conductance due to consumption of $H^{+}$ ions ( This is not visible in the curve since it is very small), during progress of titration, significant increase in conductance due to the presence of $C{H}_{3}CO{O}^{–}$ and $N{a}^{+}$ . After the end point, excess $NaOH$ will lead to rapid increase in conductance due to the increased concentration of $N{a}^{+}$ and $O{H}^{–}$.