At STP, the order of the RMS speed of molecules of , , and gases is — States of Matter and Gaseous State Chemistry Question

💡 Solution & Explanation

At any temperature, RMS speed is inversely ∝ the square root of the molar mass (√(M)). Molar masses: $H_2$ (2) < $N_2$ (28) < $O_2$ (32) < $HBr$ (81) . Therefore, speed order is $H_2$ > $N_2$ > $O_2$ > $HBr$ .