Which one of the following gases contains the least number of molecules ?

Options

A. 4.0 laughing gas
B. 3.0 phosphurus
C. 2.0 g marsh gas
D. 10.0g phosgene

Answer

a

Explanation

Number of in Laughing gas,
`(N_2O)=N/44xx4=N/11`
Number of molecules in phoshorus ,
`(P)=N/31xx3=(3N)/31`
Number of molecules in marsh gas `(CH)_4=N/99xx10=(10N)/99`
`therefore` 4.0g of laughing gas `(N_2O)` contains least number of moloecules