A solution of 1.73 g of 'A' ( non-volatile and non-electrolyte ) in 100 cc of water is found to be isotonic with a 3.42% (wt. /vol.) solution of sucrose (${\mathrm{C}}_{12}{\mathrm{H}}_{22}{\mathrm{O}}_{11}$) at same temperature. Molecular weight of ‘A’ is______g/mole. $({\mathrm{C}}_{12}{\mathrm{H}}_{22}{\mathrm{O}}_{11}=342)$