We know that, for ideal gases,enthalpy, H and internal energy, E and PV can be written as:
H = U + PV
Therefore, change in enthalpy:
ΔH = ΔU + Δ(PV) = ΔU + Δ(nRT)
In the given process, Δn = 0, since there is no change in the number of moles and ΔT = 0, since the process is isothermal.
Therefore:
ΔH = ΔU
For an isothermal process, the change in internal energy, ΔU = 0.
Hence:
ΔH = ΔU = 0
Hence change in enthalpy will be zero