Question

One mole of any substance contains $6.022 \times 10^{23}$ atoms/molecules. Number of molecules of $H_{2}SO_{4}$ present in $100 \,mL$ of $0.02\, M\, H_{2}SO_{4}$ solution is _______molecules.

• A. $12.044\times10^{20}$
• B. $6.022\times10^{23}$
• C. $1\times10^{23}$
• D. $12.044\times10^{23}$

Answer 1

Answer: (A)

Molarity $=\frac{{\text{No. of moles of solute }} \times 1000}{\text{Volume of solutions (in mL)}}$
$because 1\,M\,H_{2} SO_{4}$ contains $1$ mole of $H_{2}SO_{4}$ i n $1000\, mL$ of solutions
$\therefore 0.02 \,M\, H_{2}SO_{4}$ in $100\,mL$ of solution contains
$\frac { 0.02\times 100}{1000} = 2\times \times 10^{-3}$ mol
$ = 2 \times 10^{-3} \times 6.022\times 10^{23}$
$ = 12.044\times 10^{20}$ molecules