One mole each of CaC2, Al4C. and Mg2C3 reacts with H2O in separate open flasks at 25°C. Numerical value of the work done by the system is in order.

W=−pV2−V1=−pnRTP−0=−nRTInitial volume = 0 (being solid)Final volume = due to n moles of gas from I mole reactantCaC1mol(s)+2H2O⟶Ca(OH)2+C2H2(g)Al4C3(s)+12H2O⟶4Al(OH)3+3CH4Mg2C3      (s)+H2O⟶2Mg(OH)2+CH3−C1 mol≡CHThus, moles of C2H2=CH3−C≡CH