Volume of a gas at NTP is 1.12 × 10^–7 cc. The number of molecules is thus equal to:

(a) 3.01 × 10¹²

(b) 3.01 × 10¹⁸

(c) 3.01 × 10²⁴

(d) 3.01 × 10³⁰

Ans - (a)

1 mole of gas occupies 22.4 litres at STP
1 mole of gas contains Avogadros number of molecules = 6.022*10^23.
You have not given any units for the volume.
The answer would be (volume/22.4)*Avogadros number = (1.12*10^-7/22.4)*6.022\*10^34
= 0.3011*10^27 if volume is in litres
=0.3011*10^24 = 3.011*10^23 if volume is in m^3.
Answer is c).