A 0.10 mol dm<sup>-3</sup> aqueous solution of an acid is added slowly to 25 cm<sup>3</sup> of a 0.10 mol dm<sup>-3</sup> aqueous solution of a base - AQA - A-Level Chemistry - Question 14 - 2020 - Paper 3
Question 14
A 0.10 mol dm<sup>-3</sup> aqueous solution of an acid is added slowly to 25 cm<sup>3</sup> of a 0.10 mol dm<sup>-3</sup> aqueous solution of a base.
Which acid–base... show full transcript
Worked Solution & Example Answer:A 0.10 mol dm<sup>-3</sup> aqueous solution of an acid is added slowly to 25 cm<sup>3</sup> of a 0.10 mol dm<sup>-3</sup> aqueous solution of a base - AQA - A-Level Chemistry - Question 14 - 2020 - Paper 3
Step 1
A CH<sub>3</sub>COOH and NaOH
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Answer
At the equivalence point, acetic acid (CH<sub>3</sub>COOH) and sodium hydroxide (NaOH) will produce a salt and water. The resultant solution will contain the acetate ion, which acts as a weak base increasing the pH, but not to a very high level.
Step 2
B CH<sub>3</sub>COOH and NH<sub>3</sub>
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Answer
This combination produces ammonium acetate at the equivalence point. Ammonium ion is a weak acid, and thus the resultant pH will be lower than a solution containing a strong base.
Step 3
C HCl and NaOH
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Answer
Hydrochloric acid (HCl) is a strong acid and reacts with sodium hydroxide, a strong base, resulting in a neutral solution with a pH around 7 at the equivalence point.
Step 4
D HCl and NH<sub>3</sub>
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Answer
The reaction will result in the formation of ammonium chloride, which creates a weakly acidic solution due to the presence of the ammonium ion. This solution will have a lower pH compared to those involving stronger bases.
