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

The correct option is B 30.22
$H_{2}O$ undergoes decomposition as follows-

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

2 moles 2 moles 1 mole

36 g 4 g 32 g

$⟹$ 36 g of $H_{2}O$ gives 4 g of $H_2$ and 32 g of $O_2$

$⟹$ 34 g of $H_{2}O$ gives $\frac{4\times 34}{36}$ g of $H_2$ and $\frac{32\times 34}{36}$ $O_2$

$⟹$ 34 g of $H_{2}O$ gives 3.78 g of $H_2$ and 30.22 g of $O_2$