Question

If the temperature of an ideal gas is doubled at constant pressure, what happens to its volume?

• A. It becomes half
• B. It doubles
• C. It becomes one-fourth
• D. It remains unchanged

Hint:

At constant pressure, volume and temperature of an ideal gas are directly proportional. This is known as Charles’s Law. If temperature increases, volume increases proportionally.

Answer 1

The Correct Option is B

This is a direct application of the ideal gas law:
\[ PV = nRT \] If pressure \( P \) and number of moles \( n \) are constant, then the equation simplifies to:
\[ V \propto T \] This means that volume is directly proportional to temperature (in Kelvin).
So, if the temperature is doubled:
\[ T_2 = 2T_1 \quad \Rightarrow \quad V_2 = 2V_1 \] Hence, the volume also doubles.
Let’s say the initial temperature is \( 300\,K \), and volume is \( V \). After doubling the temperature to \( 600\,K \), the volume becomes \( 2V \).