The correct option is D 20
12g of a non-volatile solute dissolved in 108g of water produces the relative lowering of vapour pressure of 0.1. The molecular mass of the solute is 20.
0.1= 12 g × 18 g/mol 108 g ×M2
M2= 20 g/mol
Note: W1 and W2 are weights of water and solute respectively.
M1 and M2 are molecular weights of water and solute respectively.