An ideal-gas mixture consists of 30 percent helium and 70 percent argon gases by mass. The mixture

Question:

An ideal-gas mixture consists of 30 percent helium and 70 percent argon gases by mass. The mixture is now expanded isentropically in a turbine from 400°C and 1.2 MPa to a pressure of 200 kPa. The mixture temperature at turbine exit is
(a) 195°C (b) 56°C (c) 112°C
(d) 130°C (e) 400°C