KCET 2025 Chemistry Paper

Statement I
For an adiabatic process Q=0.
If "work done" W is taken positive when done on the system, then the first law gives
∆U=Q+W=0+W=W
Thus if work is done on the system ( W>0 ), its internal energy increases ( ∆U>0 ).
Statement II
In a free (Joule) expansion the external pressure P‌ext ‌=0, so
W=∫PextdV=0
Hence no work is done during the free expansion of an ideal gas.
Both statements are therefore true.