(d), Work done = PdV = nRTn=0.5T = 273 KR = 2 K/CalBoth, temperature and pressure are constant, we cannot conclude that the process is isothermal or isobaric.

Given:
- Initial volume of H2 gas (V1) = 1 g
- Final volume of H2 gas (V2) = 2 * V1
- Initial pressure of H2 gas (P1) = 1 atm (STP conditions)
- Final pressure of H2 gas (P2) = P1 (since the temperature is constant)
- Work done during the expansion process = ?

Formula for work done:
The work done during an isothermal expansion or compression process can be calculated using the formula:
Work = -P * ΔV

Where:
P is the pressure of the gas
ΔV is the change in volume of the gas (V2 - V1)

Solution:

Step 1: Calculate the change in volume (ΔV)
Since the final volume is double the initial volume, we have:
ΔV = V2 - V1
= 2 * V1 - V1
= V1

Step 2: Calculate the work done using the formula:
Work = -P * ΔV

Since the pressure remains constant during the process, we can substitute P1 for P:
Work = -P1 * ΔV

Step 3: Convert the work done into calories
1 calorie = 4.18 joules

We know that 1 atm = 101.3 J
Therefore, 1 cal = 101.3 J / 4.18
= 24.27 J

So, the work done in calories can be calculated as:
Work (cal) = Work (J) / 24.27

Substituting the values, we get:
Work (cal) = -P1 * ΔV / 24.27

Step 4: Substitute the given values to calculate the final result:
P1 = 1 atm
ΔV = V1 = 1 g

Work (cal) = -1 atm * 1 g / 24.27

Simplifying the expression, we get:
Work (cal) = -0.0412 cal

Since work cannot be negative, we take the absolute value:
Work (cal) = 0.0412 cal

Answer:
The work done during the expansion process is approximately 0.0412 calories.
Therefore, the correct answer is not provided in the options given.