Question

The oxygen obtained from 72 kg of water is

• A. 72 kg
• B. 46 kg
• C. 50 kg
• D. 64 kg

Answer 1

Answer: (D)

Key Idea: First-write the reaction for dissociation of water and then with help of unitary method find how much oxygen is produced from 72 kg of water. $\underset{\begin{array}{c}2(1\times 2+16)\\ =36\text{kg}\end{array}}{2H_{2}O}\to 2H_2+\underset{\begin{array}{c}2\times 16\\ =32\text{kg}\end{array}}{O_2}$ $\because$ $36\text{ kg}{\text{H}}_{2}O$ produces oxygen $=32\text{kg}$ $\therefore$ $\text{72}\text{kg}{\text{H}}_{\text{2}}\text{O}$ process oxygen $=\frac{32}{36}\times 72$ $=64kg$