Question

Saturated solution of $KNO_{3}$ is used to make salt bridge because}

• A. Velocity of $K^{+}$ is greater than $NO_{3}^{-}$
• B. Velocity of $NO_{3}^{-}$ is greater than $K^{+}$
• C. Velocity of $K^{+}$ approximately equal to $NO_{3}^{-}$
• D. $KNO_{3}$ is highly soluble in water

Hint:

Salt bridge electrolytes must have ions with nearly identical ionic mobility.

Answer 1

The Correct Option is C

Step 1: Concept
A salt bridge maintains electrical neutrality in the two half-cells of a galvanic cell.

Step 2: Meaning
For the bridge to work effectively without creating a liquid junction potential, the cations and anions must move at similar speeds.

Step 3: Analysis
If one ion moved much faster, a charge imbalance would develop at the ends of the bridge.

Step 4: Conclusion
$KNO_{3}$ is chosen because the transport numbers (velocities) of $K^{+}$ and $NO_{3}^{-}$ are nearly equal. Final Answer: (C)