Question

Which of the following has the least number of molecules?

• A. $1\times {10}^{23}$ molecules of ${SO}_2$ gas
• B. $1$ mole of ${SO}_2$ gas
• C. $11.2$ litres of ${SO}_2$ gas at S.T.P
• D. $40$ gm of ${SO}_2$ gas

Answer 1

Answer: (A)

$1\times {10}^{23}$ molecules of ${SO}_2$ gas

A. No. of molecules of $S{O}_2$ gas is $1\times {10}^{23}$ molecules

B. One mole of${SO}_2$gas

= $6.023\times {10}^{23}$ molecules

C. $11.2litresof{SO}_2$ gas

= $\frac{11.2}{22.4}\times 6.023\times {10}^{23}$molecules

= $3.01\times {10}^{23}$ molecules

D. 40 gms of ${SO}_{2}gas$

= $\frac{40}{64}\times 6.023\times {10}^{23}$ molecules

Hence $1\times {10}^{23}$molecules of ${SO}_2$ gas having smallest number of molecules.
Option A is correct.