Question

The pressure of a gas kept in an isothermal container is 200 kPa. If half the gas is removed from it, the pressure will be
(a) 100 kPa
(b) 200 kPa
(c) 400 kPa
(d) 800 kPa.

Answer 1

400 because 200 kpa is the iso thermal

Answer 2

Answer is Option (a)

Explanation:

Let n = Number of Mole  

Applying equation of state, we get

PV=nRT

$P = \frac {nRT}{V}$

or $2 \times 10^5 = \frac {nRT}{V}$ ""(1)

When half of the gas is removed, number of moles left behind = $\frac {n}{2}$

Let the pressure be P'

P' = $\frac {nRT}{2V}$

Now,  

P' = $\frac {1}{2} \times 2 \times 10^5 = 10^5$ (from (1))

= 100kPa