Some Basic Concepts of Chemistry - Result Question 40 — JEE PYQ Chapterwise

Answer:

Correct Answer: 44. $\left(5 \times 10^{-19} \mathrm{~m}^2\right)$

Solution:

44. Initial millimol of $\mathrm{CH}_3 \mathrm{COOH}=100 \times 0.5=50$ millimol of $\mathrm{CH}_3 \mathrm{COOH}$ remaining after adsorption

$=100 \times 0.49=49$

$\Rightarrow$ millimol of $\mathrm{CH}_3 \mathrm{COOH}$ adsorbed $=50-49=1$

$\Rightarrow$ number of molecules of $\mathrm{CH}_3 \mathrm{COOH}$ adsorbed

$=\frac{1}{1000} \times 6.023 \times 10^{23}=6.023 \times 10^{20}$

$\Rightarrow$ Area covered up by one molecule $=\frac{3.01 \times 10^2}{6.02 \times 10^{20}}$

$=5 \times 10^{-19} \mathrm{~m}^2$