Question

At constant temperature a gas at the pressure of 540 mm Hg. At
what pressure it volume will decreased by 25%.

Answer 1

According to the Boyel's Law: At constant temperature, the product of pressure and volume of a fixed amount of a gas is constant. Also, if at constant temperature,

V 1 = Volume of a gas at pressure P1

V 2 = Volume of the same gas at pressure P2

Then,

P1V1 = P2V2

According to question:

P1 = 540 mm Hg

Let V1 = 100 L

P2 = ?

V2 = Volume is 60% lesser than V1 = 100-60 = 40 L

So P2 = P1V1/ V2

= 540 mm Hg x 100 L/40 L

= 1350 mm Hg