Question

Two oxides of a certain metal were separately heated in a current of hydrogen until constant weights were obtained. The water produced in each case was carefully collected and weighed. $2g$ of each oxide gave respectively $0.2517g$ and $0.4526g$ of water. This observation illustrates

• A. law of conservation of mass
• B. law of constant proportions
• C. law of multiple proportions
• D. law of reciprocal proportions

Answer 1

Answer: (C)

Weight of $H_{2}O$ from oxides give weight of oxygen and metal in oxide.

$0.2517g{H}_{2}O$ contains oxygen $=\frac{16}{18}\times 0.2517=0.2237g$

Mass of metal $=2-0.2237=1.7763g$

$0.4526g{H}_{2}O$ contains oxygen $=\frac{16}{18}\times 0.4526=0.4023g$

Mass of metal $=2-0.4023=1.5977g$

Thus, we can get the weight of oxygen with constant weight of metal $(1g)$ for other oxides, which two are in simple ratio of $0.125:0.251=1:2$