Question

In an experiment, 2.4 g of iron oxide on reduction with hydrogen yields 1.68 g of iron. In another experiment, 2.9 g of iron oxide gives 2.03 g of iron on reduction with hydrogen. This illustrates:

• A. The law of definite proportions
• B. The law of multiple proportions
• C. The law of conservation of energy
• D. The law of reciprocal proportions

Answer 1

The correct option is A The law of definite proportions

$\text{Mass of iron in experiment}I=1.68g$
$\text{Mass of oxygen in experiment}I=0.72g$
$\text{Mole ratio of Fe : O}=0.03:0.045=1:1.5=2:3$

$\text{Mass of iron in experiment}II=2.03g$
$\text{Mass of oxygen in experiment}II=0.87g$
$\text{Mole ratio of}Fe:O=0.03625:0.054375$
$=1:1.5=2:3$

The composition of iron oxide is constant in both the experiments. Hence, this illustrates the law of definite proportions.