The root mean square speeds at STP for the gases H2,N2,O2 and HBr are in the order

Question

The root mean square speeds at STP for the gases H2,N2,O2 and HBr are in the order (A) H2 < N2 < O2 < HBr (B) HBr < O2 < N2< H2 (C) H2 < N2 = O2< Hbr (D) HBr < O2 < H2 < N2

Tardigrade Admin · Accepted Answer

The root mean square velocity of gas molecule at
STP is given by

U_{rms} = \frac{3 RT}{M}

∴

As the molar mass of gas increases, then

U_{rms}

will decrease, so the order of

U_{rms}

of these gases is

H B r < O_{2} < N_{2} < H_{2}

Q. The root mean square speeds at STP for the gases $H_{2}, N_{2}, O_{2}$ and HBr are in the order

$H_{2} < N_{2} < O_{2} < H B r$

$H B r < O_{2} < N_{2} < H_{2}$

$H_{2} < N_{2} = O_{2} < H b r$

$H B r < O_{2} < H_{2} < N_{2}$

The root mean square velocity of gas molecule at
STP is given by
$U_{rms} = \frac{3 RT}{M}$
$∴$ As the molar mass of gas increases, then $U_{rms}$
will decrease, so the order of $U_{rms}$ of these gases is
$H B r < O_{2} < N_{2} < H_{2}$

Q. The root mean square speeds at STP for the gases H2​,N2​,O2​ and HBr are in the order

H2​<N2​<O2​<HBr

HBr<O2​<N2​<H2​

H2​<N2​=O2​<Hbr

HBr<O2​<H2​<N2​