Question

The number of molecules in 100m L of 0.02N $H_2SO_4$ is

• A. $6.02 \times 10^{22}$
• B. $6.02 \times 10^{21}$
• C. $6.023 \times 10^{20}$
• D. $6.02 \times 10^{18}$

Answer 1

Answer: (C)

For $H_2SO_4$,
Normality, N = 2M
or M = $\frac{N}{2} = \frac{0.02}{2} = 0.01$
Moles of $H_2SO_4 = \frac{0.01 \times 100}{1000} = 1 \times 10^{-3}$
$\therefore $ Number of molecules in 100 mL of 0.02 N
$H_2SO_4 = 1 \times 10^{-3} \times N_A $
= $1 \times 10^{-3} \times 6.023 \times 10^{23} $
= $6.023 \times 10^{20}$