Question 1a

Marks: 2

a)

Explain why an ammonium ion can not behave as a Brønsted-Lowry base.

[2]

Key Concepts

Brønsted–Lowry Acids & Bases

Question 1b

Marks: 2

b)

State and explain the acid-base character of aqueous ammonia at 298 K.

[2]

Key Concepts

Brønsted–Lowry Acids & Bases
Strong & Weak Acids & Bases

Question 1c

Marks: 2

c)

Acids can be classed as monoprotic, diprotic and triprotic. Sulfuric acid is a diprotic acid.

i)

State the equation for the first ionisation step of sulfuric acid, including state symbols.

ii)

Label the conjugate acid and base pairs in your answer to part i).

Key Concepts

Conjugate Acid-Base Pairs

Question 1d

Marks: 1

d)

The second ionisation step is for the ionisation of sulfuric acid is as follows.

HSO₄^- (aq) + H₂O (aq) ⇌ SO₄^2-(aq) + H₃O⁺ (aq)

Suggest why the second ionisation step reaches equilibrium.

Key Concepts

Conjugate Acid-Base Pairs
Strong & Weak Acids & Bases

Question 2a

Marks: 2

a)

Sodium hydrogen carbonate solution, NaHCO₃ (aq) , can act as an amphiprotic species. State the equation for the reaction fo NaHCO₃ (aq) with the following compounds:

i)

Sodium hydroxide solution.

[1]

ii)

Hydrochloric acid.

[1]

Key Concepts

Amphiprotic Species

Question 2b

Marks: 3

b)

Using your answer to part a) i) and ii), explain why NaHCO₃is amphiprotic.

[3]

Key Concepts

Amphiprotic Species

Question 2c

Marks: 3

c)

Phosphine is usually prepared by heating white phosphorus, one of the allotropes of phosphorus, with concentrated aqueous sodium hydroxide.

The equation for the reaction is.

P₄ (s) + 3OH⁻ (aq) + 3H₂O (l) → PH₃ (g) + 3H₂PO₂⁻(aq)

Identify the amphiprotic species in this reaction giving the formulas of both species it is converted to when it behaves in this manner.

[3]

Key Concepts

Amphiprotic Species

Question 2d

Marks: 4

d)

1.68 g of white phosphorus was used to make phosphine

i)

Calculate the amount, in mol, of white phosphorus used.

[1]

ii)

This phosphorus was reacted with 50.0 cm³ of 3.00 mol dm⁻³ aqueous sodium hydroxide. Deduce, showing your working, which was the limiting reagent.

[1]

iii)

Determine the excess amount, in mol, of the other reagent.

[1]

iv)

Using section 2 of the data booklet. Determine the volume of phosphine, measured in cm³ at standard temperature and pressure, that was produced.

[1]

Key Concepts

Reacting Masses & Limiting Reactants
Molar Gas Volume

Question 3a

Marks: 2

a)

Oxalic acid, H₂C₂O₄, is a weak diprotic acid and can be used in titrations. State the equation for the reaction of oxalic acid with sodium hydroxide.

[2]

Key Concepts

Acid-Base Titrations
Neutralization

Question 3b

Marks: 2

b)

The ionisation of oxalic acid occurs in two steps. State equations for both of these steps.

[2]

Key Concepts

Comparing Strong & Weak Acids
Brønsted–Lowry Acids & Bases

Question 3c

Marks: 3

c)

Tartaric acid shown below behaves as a Brønsted-Lowry acid when it reacts with calcium hydroxide, Ca(OH)₂. Sketch the structure of the salt formed from this reaction.

[3]

Key Concepts

Brønsted–Lowry Acids & Bases
Making Salts

Question 4a

Marks: 4

Using ionic equations state how HPO₄^2-can behave as an amphiprotic and amphoteric species.

Key Concepts

Amphiprotic Species

Question 4b

Marks: 2

Gallium oxide behaves as an amphoteric oxide. State two equations to show how gallium oxide reacts with a strong monoprotic acid and strong base.

Reaction with strong monoprotic acid .........................................................................................................................................

Reaction with strong base .........................................................................................................................................

[2]

Key Concepts

Amphiprotic Species

Question 4c

Marks: 1

c)

Identify the Br∅nsted-Lowry acids in the following reaction.

CH₃CH₂O^- (aq) + H₂O(l)

⇌

CH₃CH₂OH (aq) + OH^- (aq)

[1]

Key Concepts

Brønsted–Lowry Acids & Bases

DP IB Chemistry: HL

Topic Questions

8.1 Theories & Reactions of Acids & Bases

Question 1a

Key Concepts

Question 1b

Key Concepts

Question 1c

Key Concepts

Question 1d

Key Concepts

Question 2a

Key Concepts

Question 2b

Key Concepts

Question 2c

Key Concepts

Question 2d

Key Concepts

Question 3a

Key Concepts

Question 3b

Key Concepts

Question 3c

Key Concepts

Question 4a

Key Concepts

Question 4b

Key Concepts

Question 4c

Key Concepts

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