Govt Exams
Using Henderson-Hasselbalch equation: pH = pKa = -log(1.8 × 10⁻⁵) ≈ 4.74 (when [acid] = [salt])
Osmotic pressure depends on solute nature because it involves membrane interactions. Other colligative properties depend only on number of solute particles
Using Dalton's law: Partial pressure = Mole fraction × Total pressure. P(O₂) = (2/(2+3)) × 5 = (2/5) × 5 = 2 atm.
If pH = 2, then [H⁺] = 10⁻² = 0.01 M. For a 0.1 M HCl solution, α = [H⁺]/C₀ = 0.01/0.1 = 0.1. However, HCl is a strong acid with α ≈ 1.0 (essentially complete dissociation).
Colligative properties (boiling point elevation, freezing point depression, osmotic pressure, vapour pressure lowering) depend only on the number of solute particles, not on their chemical nature.
Using Raoult's law for partial pressures and ideal solutions: Total P = P₁X₁ + P₂X₂. Solving for mole fraction of ethanol: X_ethanol = (Total P - P_water)/(P_ethanol - P_water) ≈ 0.30
ΔH = Ea(forward) - Ea(reverse) = 50 - 35 = 15 kJ/mol. The positive value indicates an endothermic reaction.
A process is spontaneous when ΔG < 0. Neither ΔH nor ΔS alone determines spontaneity; it depends on their combined effect at a given temperature.
This is an exothermic reaction (ΔH negative). By Le Chatelier's principle, decreasing temperature shifts equilibrium towards the products (right), favoring the exothermic forward reaction.
At equilibrium, Kc = kf/kr. Given Kc = 4, this means kf = 4kr, indicating the forward reaction is faster than the reverse reaction.