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)

64 kg

Answer 2

The oxygen obtained from $72 kg$ of water is obtained by the following equation. $\underset{\overset{2(2+16)}{=36}}{2 H _{2} O} \longrightarrow \underset{\overset{(2\times 16)}{=32}}{2 H _{2}+ O _{2}}$ Therefore, $36\, kg$ of water produce $32\, g$ of oxygen. Hence, $72\, kg$ of water produce oxygen $=\frac{32 \times 72}{36}=64\, kg$