Question

Pure water will auto-ionize to produce a hydronium ion and a hydroxide ion:

2H2O --> H3O+ + OH-

comapare the componets within the final reaction mixture. It would contain

A) More water molecules because water is turner acid and base than H3O+ and OH-

B) More water molecules because water is a weaker acid and use than H3O+ and OH-

C) More H3O+ and OH- because the ions are stronger acid and bases than water molecules

D) More H3O+ and OH- because the ions are weaker acids and bases than water molecules

Answer 1

Pure water auto ionise to produce H3O+ (hydronium) and OH- (hydroxide) ion at a given temperature.

2H2O(l). —> H3O+ + OH-

On comparing the components of the final reaction mixture ,the correct statement from the below is option B i.e more water molecules are formed because water is a weaker acid and base than H3O+ and OH-.

H3O+ (hydronium ion) is the stronger acid than H2O because oxygen carry +ve charge so it can easily donate proton than H2O. OH- (hydroxide ion) is stronger base than H2O because hydroxide ion carry negative charge hence can easily accept proton.Hence the given chemical reaction more shift towards weaker side of water i.e backward direction to attain equilibrium.

Product of molar conconcentration H3O+ ion and OH- at a given temperature is called Ionic product of water(Kw) which is equal to 10^-14 at 25°c. If we take 1 liter of pure water i.e 55.55 moles then only 10^-6 moles water will autoionise into H3O+ and OH- which is very small because of above reason.