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One litre of an aqueous solution is formed from mixing equal volumes of 0.2 mol L⁻¹ hydrochloric acid (HCl) and 0.2 mol L⁻¹ sodium chloride (NaCl) - HSC - SSCE Chemistry - Question 18 - 2017 - Paper 1
Question 18
One litre of an aqueous solution is formed from mixing equal volumes of 0.2 mol L⁻¹ hydrochloric acid (HCl) and 0.2 mol L⁻¹ sodium chloride (NaCl). How effective is... show full transcript
Worked Solution & Example Answer:One litre of an aqueous solution is formed from mixing equal volumes of 0.2 mol L⁻¹ hydrochloric acid (HCl) and 0.2 mol L⁻¹ sodium chloride (NaCl) - HSC - SSCE Chemistry - Question 18 - 2017 - Paper 1
Step 1
How effective is the buffer?
Answer
The solution can be considered effective because the chloride ion (Cl⁻) acts as the conjugate base of hydrochloric acid (HCl), a strong acid. While HCl itself is a strong acid and will not produce a buffer on its own, the presence of Cl⁻ provides the necessary component to maintain pH stability upon the addition of small amounts of acid or base. Thus, mixing these components allows the solution to resist changes in pH, meeting the definitions of a buffer.