Question

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)3:16. (b)1:4

(c)7:32. (d)1:8​

Answer 1

Answer:

Explanation:

the answer is (C)

weight of 7 moles of oxygen molecule=7*32=224

weight of 32 moles of n2=896

ratio of masses =224/896=1:4

hence proved

Answer 2

let the mass of O2 in a mixture is "a" gram .

Now mass of N2 is equal to 4a grams .

For O2,

Molecular mass = 32 gram=1 mole

Now "a"gm= 1/32×a= a/32 moles

Number of molecules in O2=

a/32×6.022×10^23

For N2,

Molecular mass=28 g =1 mole

For "4a"gm=1/28×4a=a/7moles

Number of molecules of N2=

a/7×6.022×10^23

Now ratio= a/32×6.022×10^23 ÷ a/7×6.022×10^23

=7/32=7:32