Question

explain why solutions of hydrochloric acid and ethanoic acid with the same concentration in mol/dm have difeerent pH

Answer 1

Answer:

Explanation:

Hydrocholoric acid is a strong acid-all of the acid molecules will release their protons into a solution, making it very acidic. Ethanoic acid, on the other hand, is a weak acid-it will only donate some of its hydrogen ions into a solution, making it less acidic than hydrochloric acid solution.

Answer 2

The solution of hydrochloric acid and ethanoic acid with same concentration have different pH due to difference in their acidic strength.

This can be explained as:

• According to Bronsted Lowry's theory of acid and base, acids are classified according to their tendency for donating a proton (H + ion) and forming hydroxonium ion (H3O + ion) in the solution.

• Acids have different tendency for donating proton, making them strong or weak acids.

• When hydrogen chloride dissolves in solution, the reverse reaction is so little and complete dissociation of ions take place in the solution.

                       H2O + HCL ⇄ (H3O + ion) + (Cl - ion)

• When ethanoic acid dissolves in solution it produces hydroxonium ions and ethanoate ions, but the back reaction is more successful than the forward reaction. In the solution, it does not completely separate.

                    H20 + CH3COOH ⇄ (Ch3COO - ion) + (H3O +)

• The measure of H + ions that dissociate and enter the solution is the pH of acid.

• Hence, we can conclude that at the same concentration in mol/dm, hydrochloric acid (strong acid) has a lower pH while ethanoic acid (weak acid) has a higher pH.