At 25°C the ionization constant of water is Kw = 10-14 mol2dm-6. At 65°C, its value changes to Kw = 2.29 x 10^-14 mol2dm-6. This shows that the dissociation of water into ions is
Correct answer: C. An endothermic process
- A. An irreversible reaction
- B. An exothermic process
- C. An endothermic process
- D. A process where no heat change occurs
Explanation
With an increase in temperature, the Kw value increases and the concentration of ions increases, showing that an increase in temperature favors the forward reaction. Indicating that the forward reaction is endothermic.H2O → H+ (aq) + OH- (aq)
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About Chemical Equilibrium
Reversible reactions reach dynamic equilibrium when forward and reverse rates become equal, and Le Chatelier's principle predicts the effect of changing concentration, pressure or temperature. The chapter also covers solubility product, the common ion effect, buffer action and the conditions used in Haber's process, with equilibrium shifts distinguished from changes in the equilibrium constant.
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