On reduction with hydrogen, 3.6 g of an oxide of metal left 3.2 g of metal. If the vapour density of metal is 32, the simplest formula of the oxide would be

As we know thatEquivalent weight = weight  of metalweight  of oxygen×8                                 =3.20.4 ×  8=64Vapour  density=mol.wt2Mol. wt. = 2 x V.D. = 2 x 32 = 64As we know that, valency of metal  n = mol.  wteq. wt=6464=1Suppose, the formula of metal oxide be M2On. Hence the formula of metal oxide = M2O.