40% of HI undergoes decomposition to H₂ and I₂ at 300 K. $$\Delta$$G$$^\Theta $$ for this decomposition reaction at one atmosphere pressure is __________ J mol^$$-$$1. [nearest integer]

(Use R = 8.31 J K^$$-$$1 mol^$$-$$1 ; log 2 = 0.3010, ln 10 = 2.3, log 3 = 0.477)

50 mL of 0.1 M CH₃COOH is being titrated against 0.1 M NaOH. When 25 mL of NaOH has been added, the pH of the solution will be _____________ $$\times$$ 10^$$-$$2. (Nearest integer)

(Given : pK_a (CH₃COOH) = 4.76)

log 2 = 0.30

log 3 = 0.48

log 5 = 0.69

log 7 = 0.84

log 11 = 1.04

PCl₅ dissociates as

PCl₅(g) $$\rightleftharpoons$$ PCl₃(g) + Cl₂(g)

5 moles of PCl₅ are placed in a 200 litre vessel which contains 2 moles of N₂ and is maintained at 600 K. The equilibrium pressure is 2.46 atm. The equilibrium constant K_p for the dissociation of PCl₅ is __________ $$\times$$ 10^$$-$$3. (nearest integer)

(Given : R = 0.082 L atm K^$$-$$1 mol^$$-$$1; Assume ideal gas behaviour)

2O₃(g) $$\rightleftharpoons$$ 3O₂(g)

At 300 K, ozone is fifty percent dissociated. The standard free energy change at this temperature and 1 atm pressure is ($$-$$) ____________ J mol^$$-$$1. (Nearest integer)

[Given : ln 1.35 = 0.3 and R = 8.3 J K^$$-$$1 mol^$$-$$1]