Question

An ideal gas undergoes isothermal expansion at constant pressure. During the process :

• A. enthalpy increases but entropy decreases.
• B. enthalpy remains constant but entropy increases
• C. enthalpy decreases but entropy increases.
• D. Both enthalpy and entropy remain constant .

Answer 1

Answer: (D)

Both enthalpy and entropy remain constant .

Answer 2

$\Delta H = nC _{ p } \Delta T =0$ $\Delta S = nR \ln \left( V _{ f } / V _{ i }\right) \geq \,0$