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A 0.1 mol L⁻¹ solution of hydrochloric acid has a pH of 1.0, whereas a 0.1 mol L⁻¹ solution of citric acid has a pH of 1.6 - HSC - SSCE Chemistry - Question 20 - 2001 - Paper 1
Question 20
A 0.1 mol L⁻¹ solution of hydrochloric acid has a pH of 1.0, whereas a 0.1 mol L⁻¹ solution of citric acid has a pH of 1.6. (a) State ONE way in which pH can be mea... show full transcript
Worked Solution & Example Answer:A 0.1 mol L⁻¹ solution of hydrochloric acid has a pH of 1.0, whereas a 0.1 mol L⁻¹ solution of citric acid has a pH of 1.6 - HSC - SSCE Chemistry - Question 20 - 2001 - Paper 1
Step 1
Step 2
Explain why the two solutions have different pH values.
Answer
The different pH values of the hydrochloric acid and citric acid solutions are due to the nature of the acids. Hydrochloric acid (HCl) is a strong acid, meaning it completely dissociates in solution, resulting in a higher concentration of hydrogen ions (H⁺). In contrast, citric acid is a weak acid; it does not completely dissociate, thus generating fewer hydrogen ions in solution. The pH is a logarithmic scale reflecting the concentration of H⁺, so the stronger dissociation of hydrochloric acid leads to a lower pH value compared to citric acid.