Question

The number of molecules contained in $2$ g of $H_2$ is the same as the number of atoms in:

• A. $1$ g of $H_2$
• B. $2$ g of $H_2$
• C. $71$ g of $C{l}_2$
• D. $28$ g of $N_2$

Answer 1

The correct option is A $1$ g of $H_2$

$2$ g of $H_2=1$ mole
$\therefore$ $1$ mole of $H_2$ contains $6.022\times {10}^{23}$ molecules or $2\times 6.022\times {10}^{23}$ atoms.
$1$ g of $H_2=0.5$ moles
$\therefore$ $0.5$ mole of $H_2$ contains $3.011\times {10}^{23}$ molecules or $6.022\times {10}^{23}$ atoms.

Thus, the number of molecules contained in $2$g of $H_2$ is same as the number of atoms in $1$ g of $H_2$.