The velocity of sound is greater in hydrogen or in oxygen at same temperature?

Why the velocity of sound is greater in moist air than dry air?

Will the velocity be equal of two different ideal gas at same temperature? Give reason.

The velocity of sound in hydrogen is 1270 m*s^(-1) "at" 0^(@) C and the frequency of a fork is 335 Hz . Find the distance travelled by sound in hydrogen at 0^(@) C and 30^(@) C in the time in which the fork completes 71 vibrations .

0.76 g of a mixture of hydrogen and oxygen gases has a volume of 2L temperature of 300 K and pressure of 10^5 N.m^-2 . Find out the individual masses of hydrogen and oxygen in the mixture.