Q7 / 160 · AP EAMCET 2013 · Chemistry

At $T(\mathrm{~K})$, the ratio of kinetic energies of $4 \mathrm{~g}$ of $\mathrm{H}_2(g)$ and $8 \mathrm{~g}$ of $\mathrm{O}_2(g)$ is

  • A
    $1: 4$
  • B
    $4: 1$
  • C
    $2: 1$
  • Correct answer
    D
    $8: 1$

Solution

$\mathrm{KE}=\frac{3}{2} R T$ for 1 mole of the gas. $\because 4 \mathrm{~g}$ of $\mathrm{H}_2$ gas has 2 moles of $\mathrm{H}_2$ $\therefore$ It has 2 times KE as compared to 1 mole of gas But $8 \mathrm{~g}$ of $\mathrm{O}_2$ gas has $1 / 4$ moles of $\mathrm{O}_2$; $\therefore$ It has one fourth part of the KE as compared to 1 mole of gas. Hence, ratio of $\mathrm{KE}$ of $\mathrm{H}_2$ and $\mathrm{O}_2$ $$ \mathrm{KE}_{\mathrm{H}_2}: \mathrm{KE}_{\mathrm{O}_2}=2: \frac{1}{4}=8: 1 $$

Hence, the correct answer is option: 'D'.

Relevant Questions