Question

If $r_{1},\, r_{2}$ and $r_{3}$ represent the most probable speeds of three different gases at the same temperature as shown in figure with molar masses $M_{1},\, M_{2}$ and $M_{3}$ respectively. The correct order of molar masses of these gases is

• A. $M_{1}>M_{3}>M_{2}$
• B. $M_{3}>M_{2}>M_{1}$
• C. $M_{2}>M_{1}>M_{3}$
• D. $M_{2}>M_{3}>M_{1}$

Answer 1

Answer: (C)

In the direction of $x$ - axis $r_{3}$ increases and

for same tamperature most probable speed

$\propto \frac{1}{\sqrt{\text { molar mass }(M)}}$

Thus, $M_{2}>M_{1}>M_{3}$.