Question
Saturated solution of $$KN{O_3}$$ is used to make ‘salt—bridge' because
A.
Velocity of $${K^ + }$$ is greater than that of $$NO_3^ - $$
B.
velocity of $$NO_3^ - $$ is greater than that of $${K^ + }$$
C.
velocities of both $${K^ + }$$ and $$NO_3^ - $$ are nearly the same
D.
$$KN{O_3}$$ is highly soluble in water
Answer :
velocities of both $${K^ + }$$ and $$NO_3^ - $$ are nearly the same
Solution :
The salt used to make ‘salt—bridge’ must be such that the ionic mobility of cation and anion are of comparable order so that they can keep the anode and cathode half cells neutral at all times. $$KN{O_3}$$ is used because velocities of $${K^ + }$$ and $$NO_3^ - $$ ions are nearly same