Between 0.1 (M) `NH_(4)OH` and 0.1 (M) NaOH solutions, which one has a greater conductivity?

Explanation

NaOH is a strong electrolyte. It dissociates almost completely in water, forming `Na^(+) and OH^(-)` ions, `[NaOH(aq)rarrNa^(+)(aq)+OH^(-)(aq)]`. On the other hand, `NH_(4)OH` is a weak electrolyte and undergoes partial dissociation in water :
`NH_(4)OH(aq)hArr NH_(4)^(+)(aq)+OH^(-)(aq).`
Hence, in the same volume of both 0.1 (N) NaOH and 0.1 (N) `NH_(4)OH` solution, the number of ions in `NaOH` solution is much greater than is `NH_(4)OH` solution. The electrical charge on each of the ions present in both the solutions is unity. Hence, there will be no difference in conductivity due to the charges on ions. But ionic velocity of `NH_(4)^(+)` is slightly greater than `Na^(+)`. So the conductivity of `NH_(4)OH` solution is expected to be a bit higher than that of `NaOH` solution. But the increase in conductivity due to ionic velocity in `NH_(4)OH` solution is more than compensated for by the increased number of ions in `NaOH` solution. Hence 0.1 (M) NaOH solution has higher conductivity than 0.1 (M) `NH_(4)OH` solution.