NTA Abhyas JEE Main2020ChemistryThermodynamics (C)Practice
Calculate the work done when 112 g iron reacts with dilute HCl at 300 K. The reaction is carried out in an open container (At mass of Fe = 56)
Options
- A600 cal
- B300 cal
- C200 cal
- D1200 cal
Correct answer
D. 1200 cal
Step-by-step solution
The number of moles of Fe taken = 112 56 = 2 So the chemical reaction is 2 F e s + 4 H C l a q → 2 F e C l 2 a q + 2 H 2 g New work done = P V 2 - V 1 Since V 2 - V 1 = V H 2 Hence volume of solids and liquids is taken as ≅ 0 So work done = P . V H 2 also P V H 2 = n R T or V H 2 = n R T P So work done = P . n R T P = n R T [ R = 2 Cal] = 2 × 2 × 300 = 1200 Cal.