The experimental values of the partial molar volume of a salt in water are found to fit the expression v_B =5.117+19.121x^1/2, where v_B =V_B/(cm³mol⁻¹) and x is the numerical value of the molality of B (x=b/b^⦵). Use the Gibbs– Duhem equation to derive an equation for the molar volume of water in the solution. The molar volume of pure water at the same temperature is 18.079 cm³mol⁻¹.