Question

Why Hydrogen has maximum rms speed at NTP ?

Answer 1

answer

Root mean square velocity is defined as the square root of the mean of the squares of the random velocities of the individual molecules of a gas. Maxwellian speed distribution law states that

c

rms

=

(

m

3kT

)

⇒c

rms

∝

T

∴

c

(rms)

2

c

(rms)

1

=

T

2

T

1

or

1

4

=

273

T

′

or T

′

=4368K

=4095

Note: At absolute zero, rms velocity of the gs molecules becomes zero, so mean KE molecule of the gas becomes zero at absolute zero.

Answer 2

Answer:

RMS speed is inversely proportional to the square root of molecular mass when temperature is constant. Since hydrogen has least molecular mass, it has highest RMS speed at NTP.

Explanation:

For more details, the formula for RMS speed is

V = $\sqrt{3RT/M}$

where, R is universal gas constant.