Question

34 g of $H_{2}O$ decomposes 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 of hydrogen and 30.22 g of oxygen.

Answer 1

The correct option is D

3.78 g of hydrogen and 30.22 g of oxygen.

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

2 moles 2 moles 1 mole

36 g 4 g 32 g

2 mole of water weighs 36 g.

2 mole of $H_2$ weighs 4 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 $O_2$.