2 mole of ideal gas at 27^oC temperature is expanded reversibly from 2 lit. to 20 lit. Find entropy change. (R = 2 cal/mol K)

Heat of combustion $$\Delta $$H^o for C_(s), H_2(g) and CH_4(g) are $$-$$ 94, $$-$$ 68 and $$-$$213 kcal/mol, then $$\Delta $$H^o for C_(s) + 2H_2(g) $$ \to $$ CH_4(g) is

In a closed insulated container a liquid is stirred with a paddle to increase the temperature which of the following is true ?

Which reaction is not feasible?