A solution of two components containing n1 moles of the 1st component and n2 moles of the 2nd component is prepared. M1 and M2 are the molecular weights of component 1 and 2 respectively. If d is the density of the solution in g mL-1, C2 is the molarity and x2  is the mole fraction of the 2nd component, then C2 can be expressed as