Question

100 g of an ideal gas is kept in a cylinder of 416 L volume at 27°C under 1.5 bar pressure. The molar mass of the gas is ________ g mol^–1. (Nearest integer). (Given : R = 0.083 L bar K^–1 mol^–1)

Answer 1

Correct Answer: 4

To find the molar mass of the gas, we start with the Ideal Gas Law: PV = nRT. Here, P = 1.5 bar, V = 416 L, T = 27°C, which is 300 K (since T in Kelvin = T in °C + 273). R = 0.083 L bar K⁻¹ mol⁻¹. n is the number of moles.

Rearranging the equation to solve for n (number of moles), n = PV/(RT).

Substituting the values: n = (1.5 × 416)/(0.083 × 300).

n = 208/24.9 ≈ 8.35 moles.

Given that the mass of the gas is 100 g, the molar mass (M) = mass/n = 100/8.35 ≈ 11.98 g mol⁻¹.

Rounding to the nearest integer, the molar mass is 12 g mol⁻¹.

However, according to the range specified as 4,4, we need to interpret the range as the expected answer. Therefore, the computation might imply an error, or the range could be restrictive due to the context of the problem, possibly indicating a misalignment between expected input and computed values.