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This quiz contains 13 questions from a mix of 1 subtopics.
What is a buffer solution?
a solution that minimises pH changes when small amounts of acid or base are added
a solution that changes pH when small amounts of acid or base are added
a solution that neutralises acid or base completely
a solution that reacts with acid or base to form a new compound
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Consider the following equilibrium for an acidic buffer solution:
HA(aq) ⇌ H+(aq) + A-(aq)
When acid is added to this acidic buffer solution, in which direction does the equilibrium shift to remove the added acid?
to the left
to the right
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Which method can be used to prepare a buffer solution based on a weak acid?
mixing a weak acid with its salt
mixing a weak acid with water
adding an alkali to a weak acid
adding an acid to a weak base
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What happens to the pH of a buffer solution as small amounts of acids or alkalis are added?
the pH changes by a small amount
the pH remains completely constant
the pH becomes neutral
the pH changes by a large amount
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What is the role of buffer solutions in the human body?
to aid in cellular recognition
to build structural components
to supply energy to cells
to control blood pH
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Which buffer system is the most important in controlling blood pH?
sulfuric acid-hydrogensulfate
carbonic acid-hydrogencarbonate
nitric acid-nitrate
phosphoric acid-hydrogenphosphate
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Consider the following equilibrium for an acidic buffer solution:
HA(aq) ⇌ H+(aq) + A-(aq)
When alkali is added to this acidic buffer solution, in which direction does the equilibrium shift to remove the added alkali?
to the left
to the right
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In which direction does the position of equilibrium shift when OH- ions are added to the carbonic acid/hydrogencarbonate buffer system?
H2CO3(aq) ⇌ H+(aq) + HCO3-(aq)
to the right
to the left
the position of equilibrium doesn't change
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What is the pH of normal healthy blood?
6.60
7.00
7.40
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In which direction does the position of equilibrium shift when H+ ions are added to the ammonia/ammonium buffer system?
NH3(aq) + H2O(l) ⇌ NH4+(aq) + OH-(aq)
to the right
to the left
the position of equilibrium doesn't change
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Calculate the pH of a buffer solution containing 0.10 mol dm-3 of CH3COOH and 0.30 mol dm-3 of CH3COONa.
Give your answer to 1 decimal place.
Ka of CH3COOH = 1.7 x 10-5 mol dm-3
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Calculate the pH of the buffer solution formed when 150 cm3 of 1.0 mol dm-3 HCOOH is mixed with 100 cm3 0.75 mol dm-3 HCOONa.
Give your answer to 1 decimal place.
Ka of HCOOH = 1.8 x 10-4 mol dm-3
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Calculate the pH of the buffer solution formed when 500 cm3 of 0.40 mol dm-3 NaOH is added to a 500 cm3 of 1.0 mol dm-3 benzoic acid.
Give your answer to 1 decimal place.
Ka of C6H5COOH = 6.3 x 10-5 mol dm-3.
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