Difference in ${\mathrm{\Lambda }}_{\mathrm{m}}^{\mathrm{o}}$ of KCl and NaCl is ‘X’ $\mathrm{mho}{\mathrm{cm}}^2{\mathrm{mole}}^{-1}$. Difference in ${\mathrm{\Lambda }}_{\mathrm{m}}^{\mathrm{o}} \mathrm{of} {\mathrm{KNO}}_3$ and ${\mathrm{NaNO}}_3$ is ‘Y’  $\mathrm{mho}{\mathrm{cm}}^2{\mathrm{mole}}^{-1}$. Correct relation between ‘X’ and ‘Y’ is

According to Kohlrausch,

“The contribution of an ion to the total molar conductance remains the same irrespective of the oppositely charged ion with which it is present in the electrolyte”.

(1) KCl and NaCl  .   .    .    cations are ${\mathrm{K}}^{+} \mathrm{and} {\mathrm{Na}}^{+}$ with a common anion ${\mathrm{Cl}}^{-}$

(2) ${\mathrm{KNO}}_3$ and ${\mathrm{NaNO}}_3$ .   .    .    cations are ${\mathrm{K}}^{+} \mathrm{and} {\mathrm{Na}}^{+}$ with a common anion ${\mathrm{NO}}_3^{-}$

So the difference in ${\mathrm{\Lambda }}_{\mathrm{m}}^{\mathrm{o}}$ is only due to ${\mathrm{K}}^{+} \mathrm{and} {\mathrm{Na}}^{+}$ which remains the same in both cases.