The boiling point of a 4 % aqueous solution of a non-volatile solute P is equal to the boiling point of X % solution of another non-volatile solute Q . The relation between their Molar masses is M _ Q =4 ~Mp . What is X ?

Step-by-step solution

The elevation in boiling point is given by T_b = K_b m , where m is the molality of the solution. Since the boiling points of the two solutions are equal, their elevations in boiling point are equal, which implies their molalities must be equal, assuming the solvent is the same and the solutes are non-volatile and non-electrolytic. Let w_P and w_Q be the masses of solutes P and Q in 100 g of solution. For a 4 % solution of P, w_P = 4 g and the mass of solvent is 100 - 4 = 96 g . The molality m_P is given by m_P = w