Question

How many molecules are present in one gram of hydrogen gas?

• A. $6.02\times {10}^{23}$
• B. $3.01\times {10}^{23}$
• C. $2.5\times {10}^{23}$
• D. $1.5\times {10}^{23}$

Answer 1

Answer: (B)

$3.01\times {10}^{23}$

$1$ mole of hydrogen gas contains $6.02\times {10}^{23}$ atoms.

$1$ molecule of hydrogen$\left(H_2\right)$ contains two atoms of hydrogen.

$\therefore$ $1$ gm of hydrogen contains $\frac{1\times 6.02\times {10}^{23}}{2}=3.01\times {10}^{23}$ molecules.

Hence, option B is correct.