Basic question of chemistry for 11th and 12th students

1.Question: The most abundant rare gas in the atmosphere is
a.He
b.Ne
c.Ar
d.Xe

Answer:-Argon is the inert gas. It is the most abundant rare gas in the atmosphere because it occurs in the earth crust with 93%.

It is a not reactive element. So for this questions Ar is the correct.

other related question;-

2.Equal masses of oxygen, hydrogen and methane are kept under identical condition.The ratio of the volumes of gasses will be
A. 2 : 16 : 2
B. 2 : 16 : 1
C. 1 : 16 : 2
D. 1 : 1 : 1

Answer ;-C

Convert the mass into moles (use the formula n=m/Mr)
m = mass and Mr = Molecular weights
Molecular weights are 32(Oxygen), 2(Hydrogen), and 16(Methane), respectively.
Since the masses are equal, you can take the mass as x. So, the number of moles would be:
n(O2) = x/32
n(H2) = x/2
n(CH4) = x/16
The ratio of their volumes is (O2) : (H2) : (CH4) = 1 : 16 : 2