Question

34 g of $H_{2}O$ is decomposed to _______ g of hydrogen and ____ g of oxygen.

• A. 30 g of oxygen and 4 g of hydrogen
• B. 16 g of oxygen and 18 g of hydrogen
• C. 32 g of oxygen and 2 g of hydrogen
• D. 3.78 g H₂ and 30.22 g O_2.

Answer 1

The correct option is D

3.78 g H₂ and 30.22 g O_2.

${2H}_{2}O$ $\to$ ${2H}_2$ + $O_2$

2 mole 2 mole 1mole

36 g 4g 32 g

2 mole of water weighs 36 g.

1 mole of $H_2$ weighs 2 g

1 mole of $O_2$ weighs 32 g

36 g $H_{2}O$ gives 4g $H_2$ and 32 g $O_2$.
So, 34 g $H_{2}O$ gives $\frac{4\times 34}{36}$ g $H_2$ and $\frac{32\times 34}{36}$ $O_2$.
So, 34 g $H_{2}O$ gives 3.78 g $H_2$ and 30.22 g $O_2$.