Question

The number of molecules in $4.25$ g of $N{H}_3$ is :

• A. $1.505\times {10}^{23}$
• B. $3.01\times {10}^{23}$
• C. $6.02\times {10}^{23}$
• D. none of these

Answer 1

The correct option is A $1.505\times {10}^{23}$

As $17$ g of $N{H}_3$ has $1$ mol.

Number of moles in $4.25g=\frac{4.25}{17}$

Number of molecules = $\frac{4.25}{17}\times N_A$$=1.505\times {10}^{23}$