Question

Two oxides of a metal M contains 50% and 40% of the metal respectively. The formula of the first oxide is MO. Then the formula of the second oxide is

(a) M₂O

(b) M₂O₃

(c) MO₂

(d) M₂O₅

Answer 1

Correct option is (b) M₂O₃

Since the metal and oxygen constitute 50% each of the mass of oxide MO, 

Atomic mass of the metal = Atomic mass of oxygen = 16 

Mass of metal M in 100 g of second oxide = 40 g 

Mole atoms of M = \(\frac{40}{16}\) = 2.5

Mole atoms of O = \(\frac{100-40}{16} \) = 3.75

Ratio of mole atoms of M and O = 2.5 : 3.75 

= 1 : 1.5

= 2 : 3