The ratio of masses of oxygen and nitrogen in a particular gaseous mix

1.	The ratio of masses of oxygen and nitrogen in a particular gaseous mixture is 1 : 4. The ratio of number of their molecule is _____.(A) 1 : 4 (B) 7 : 32 (C) 1 : 8 (D) 3 : 16
Answer» Correct option: (B) 7 : 32 Both O₂ and N₂ are diatomic. ∴ ratio of their number of molecules will be equal to ratio of their number of moles. number of moles of O₂ = \(\cfrac{Weight\,of\,O_2}{32}\) number of moles of N₂ = \(\cfrac{Weight\,of\,N_2}{28}\) number of moles of O₂ = number of moles of N₂ \(\cfrac{Weight\,of\,O_2}{32}\) = \(\cfrac{Weight\,of\,N_2}{28}\) \(\cfrac{1}{32} : \cfrac{4}{28}\) \(\cfrac{1}{32} : \cfrac{1}{7}\) ∴ ratio is 7 : 32

The ratio of masses of oxygen and nitrogen in a particular gaseous mixture is 1 : 4. The ratio of number of their molecule is _____.(A) 1 : 4 (B) 7 : 32 (C) 1 : 8 (D) 3 : 16

Answer»

Correct option: (B) 7 : 32

Both O₂ and N₂ are diatomic.

∴ ratio of their number of molecules will be equal to ratio of their number of moles.

number of moles of O₂ = \(\cfrac{Weight\,of\,O_2}{32}\)

number of moles of N₂ = \(\cfrac{Weight\,of\,N_2}{28}\)

number of moles of O₂ = number of moles of N₂

\(\cfrac{Weight\,of\,O_2}{32}\) = \(\cfrac{Weight\,of\,N_2}{28}\)

\(\cfrac{1}{32} : \cfrac{4}{28}\)

\(\cfrac{1}{32} : \cfrac{1}{7}\)

∴ ratio is 7 : 32