Statement 1 : Work done by a gas in isothermal expansion is more than the work done by the gas in the same expansion, adiabatically.

Statement 2 : Temperature remains constant in isothermal expansion, and not in adiabatic expansion

STATEMENT 1(Assertion) and STATEMENT 2(Reason). question has the 4 choices (a), (b), (c) and (d) out of which ONLY ONE is correct.

Adiabatic curve is steeper than isothermal curve. Therefore, area under adiabatic curve is smaller than the area under isothermal curve i.e, work done by the gas in adiabatic expansion is smaller than the work done by the gas in isothermal expansion. The reverse is also true. 

Isothemal Process means constant temperature process and the temperature remains constant but in adiabatic process, temperature need not be constant.

Therefore, Reason is also true but Reason does not explain Assertion