The limiting molar conductivity of HCl is $426.2 S c m^{2} mo l^{- 1}$ and the transport number of $H X^{+}$ in very dilute HCl is $0.821$ . The limiting molar conductivity of KCl is $149.9 S c m^{2} mo l^{- 1}$ . The transport number of $K X^{+}$ in very dilute KCl is closest to

Answer: A

From HCl:

λ^{\circ} (H X^{+}) = 0.821 \times 426.2 = 349.9

and

λ^{\circ} (Cl X^{-}) = 426.2 - 349.9 = 76.3 S c m^{2} mo l^{- 1}

. At infinite dilution

λ^{\circ} (Cl X^{-})

is the same in KCl (Kohlrausch), so

λ^{\circ} (K X^{+}) = 149.9 - 76.3 = 73.6

t (K X^{+}) = 73.6/149.9 = 0.491

. Option (B) is

t (Cl X^{-})

in KCl.