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Acids, bases and titration — Question 15

QCAA 2023, Paper 1 · 1 mark

Q15 · 2023 · Paper 1Unclassified1 mark

QUESTION 15

- , (HCO )

Predict how a buffer solution, consisting of carbonic acid (H2CO3) and hydrogen carbonate ions

3

would react to resist a change in pH when a small amount of hydrochloric acid is added.

+

2

+

-

-

H CO (aq)

HCO (aq) + H (aq)

CO (aq) + 2H (aq)

⇌

⇌

2 3

3

3

(A) Equilibrium shifts to the right and the [H +](aq) increases.

2 - [CO ](aq)

(B) Equilibrium shifts to the left and the

increases. 3

[H CO ](aq) increases.

(C) Equilibrium shifts to the left and the

2 3

- [HCO ](aq)

(D) Equilibrium shifts to the right and the

increases. 3

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