Question

Saturated solution of $KN{O}_3$ with agar-agar is used to make 'salt bridge' because:

• A. Size of $K^{+}$ is greater than that of $N{O}_3^{-}$
• B. Ionic mobility of $N{O}_3^{-}$ is greater than that of $K^{+}$
• C. Ionic mobilities of $K^{+}$ and $N{O}_3^{-}$ are nearly the same
• D. Both ionic mobilities and sizes of $K^{+}$ and $N{O}_3^{-}$ ions are same

Answer 1

The correct option is C Ionic mobilities of $K^{+}$ and $N{O}_3^{-}$ are nearly the same

The fuction of a salt bridge to maintain electrical neutrality of both half cells. The ionic mobilities of the ions of the solution used must have same value to maintain the electrical neutrality. So, the ionic mobilities of $K^{+}$ and $N{O}_3^{-}$ are nearly same.