Question

Which is/are correct statements about $1.7\text{g}$ of $N{H}_3$?

• A. It contains $0.3\text{mol}H-$ atom
• B. It contains $2.408\times {10}^{23}$ atoms
• C. Mass $\%$ of hydrogen is $17.65\%$
• D. It contains $0.3\text{mol}N-$ atom

Answer 1

Answer: (A), (B), (C)

The correct options are
A It contains $0.3\text{mol}H-$ atom
B It contains $2.408\times {10}^{23}$ atoms
C Mass $\%$ of hydrogen is $17.65\%$

Moles of $N{H}_3=\frac{1.7}{17}=0.1$
$N{H}_3$ has $3H$ atoms so,
Moles of $H$ atom $0.1\times 3=0.3$
Moles of $N$ atom $=0.1$
Total number of atoms $=0.1\times 4\times 6.02\times {10}^{23}$
$=2.408\times {10}^{23}$
$\%H=\frac{\text{molar mass of}H}{\text{molar mass of}N{H}_3}\times 100$
$=\frac{3\times 1}{17}\times 100=17.65\%$