Question
Two oxides of a metal M contain respectively 22.53% and 30.38% of O2. If the formula of first oxide is MO, the formula of second oxide is
(a) M2O3 (b) MO3 (c) M2O (d) M2O4
Joshi sir comment
M O
77.47 22.53
m w M 16
formula for first oxide is MO
so 77.47/M = 22.53/16
so M = 77.47*16/22.53 = 55
M O
69.62 30.38
m w 55 16
so M:O = 69.62/55:30.38/16 = 1.27:1.90
1.9/1.27 = 1.5
so formula will be M2O3