Question

$ 1.25\,g \,NH_3$ contains how many atoms?

• A. $ 10^{23}$
• B. $ 2\times 10^{23} $
• C. $ 6\times 10^{13} $
• D. $ 4\times 10^{23} $

Answer 1

Answer: (B)

No. of atoms = No. of gram molecular weight $ \times \,6.02\,\times 10^{23} \times $ atomicity
No. of atoms in $ 1.25\,g $ of $ NH_3 $
$ =\frac{1.25}{17}\times 6.02\times 10^{23}\times 4 $
$ =2.2\times 10^{23} $