Two ballons are filled, one with pure He gas and other by air, repectively. If the pressure and temperature of these ballons are same then the number of molecules per unit volume is:

Options

A. more in He filled ballon
B. same in both balloons
C. more in air fillled ballon
D. in the ratio 1:4

Answer

B

Explanation

Assuming the bllons have the same volume , as `pV=nRT. If p,V andT are the same , n the number of moles present will be the same , whether it is He or air Hence,number of molecules per unit volume will be same in both the bolloons