Edexcel International A Level Chemistry

Topic Questions

International A LevelChemistryEdexcelTopic Questions2. Energetics, Group Chemistry, Halogenoalkanes and Alcohols2.3 Redox Chemistry & Acid-Base Titrations

2.3 Redox Chemistry & Acid-Base Titrations

DownloadView
Easy
Medium
Hard
Easy
Medium
Hard
1
Sme Calculator1 mark

What is the oxidation number of chromium in Na2Cr2O7?

  • +1

  • +2   

  • +3

  • +6

Choose your answer

Did this page help you?

2
Sme Calculator1 mark

In an oxide of nitrogen, the oxidation number of nitrogen is +4.

Which is the formula of the oxide?

  • N2O

  • N2O3

  • N2O4

  • N2O5

Choose your answer

Did this page help you?

3
Sme Calculator1 mark

What is the oxidation number of phosphorus in the phosphate ion, Pstraight O subscript 4 superscript 3 minus end superscript?

  • –3

  • +3

  • +5

  • +7

Choose your answer

Did this page help you?

1a
Sme Calculator1 mark

A group of students carry out an experiment to find the concentration of chlorine, Cl2 (aq), in a solution.

Excess potassium iodide solution is added to a 10.0 cm3 sample of the chlorine solution.

Cl2 (aq) + 2I− (aq) rightwards arrow 2Cl− (aq) + I2 (aq)

The iodine produced is titrated with a solution of thiosulfate ions of known concentration, using starch indicator.

2S2O32- (aq) + I2 (aq) → S4O62- (aq) + 2I− (aq)

The concentration of the Cl2 (aq) is between 0.038 and 0.042 mol dm−3 .

What concentration of thiosulfate ions, in mol dm−3 , is required to give a titre of approximately 20 cm3 ?

  • 0.010

  • 0.020

  • 0.040

  • 0.080

Choose your answer

1b
Sme Calculator1 mark

What is the most suitable volume of 0.1 mol dm−3 potassium iodide solution, in cm3, to add to the 10.0 cm3 of chlorine solution?

  • 7.6

  • 8.0

  • 8.4

  • 10.0

Choose your answer

1c
Sme Calculator1 mark

What is the colour change at the end‐point of the titration?

  • colourless to pale yellow

  • pale yellow to colourless

  • colourless to blue‐black

  • blue‐black to colourless

Choose your answer

Did this page help you?

11 mark

Hydrogen peroxide, H2O2, breaks down into water and oxygen.

In terms of oxidation and reduction, how do hydrogen and oxygen change in this reaction?

      Hydrogen Oxygen
  ☐ A oxidised reduced
  ☐ B oxidised and reduced unchanged
  ☐ C reduced oxidised
  ☐ D unchanged oxidised and reduced

Choose your answer

Did this page help you?

21 mark

Iodate(V) ions, Ibegin mathsize 16px style O subscript 3 to the power of minus sign end style, oxidise dithionate ions, S2straight O subscript 6 superscript 2 minus end superscript, according to the equation

x Ibegin mathsize 16px style O subscript 3 to the power of minus sign end style+ y S2straight O subscript 6 superscript 2 minus end superscript+ 4H2O → z Sbegin mathsize 16px style O subscript 4 to the power of 2 minus sign end style+ 8H++ I2

What are the balancing numbers x, y and z?

      x y z
  ☐ A 2 1 2
  ☐ B 2 2 4
  ☐ C 2 5 5
  ☐ D 2 5 10

Choose your answer

Did this page help you?

31 mark

Magnesium reacts with hydrochloric acid.

Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2 (g)

Which statement about this reaction is correct?

  • magnesium atoms act as oxidising agents

  • hydrogen molecules act as reducing agents

  • hydrogen ions act as oxidising agents

  • chloride ions act as oxidising agents

Choose your answer

Did this page help you?

4
Sme Calculator1 mark

The formulae of four ions are shown.

Formula of ion
CrO42-
AlO2-
[Fe(CN)6]4-
[CrCl2(H2O)4]+

How many of these ions contain a metal with an oxidation number of +3?

  • one

  • two

  • three

  • four

Choose your answer

Did this page help you?

5a1 mark

This question is about the reaction shown.

2KMnO4 + xH2C2O4 + yH2SO4 → 2MnSO4 + K2SO4 + 10CO2 + zH2O

a)
 What values of x, y and z are needed to balance the equation?

      x y z
  ☐ A 5 6 8
  ☐ B 10 3 4
  ☐ C 5 3 8
  ☐ D 10 6 4

Choose your answer

5b
Sme Calculator1 mark
b)
What is the reducing agent in the reaction?

  • H+

  • C2O42-

  • MnO4

  • SO4

Choose your answer

Did this page help you?

6
Sme Calculator1 mark

Which name is correct for the ion Sstraight O subscript 4 superscript 2 minus end superscript ?

  • sulfate(II)

  • sulfate(IV)

  • sulfate(VI)

  • sulfate(VIII)

Choose your answer

Did this page help you?

7
Sme Calculator1 mark

A diprotic acid, H2A, was titrated with sodium hydroxide solution.

H2A (aq) + 2NaOH (aq) rightwards arrow Na2A (aq) + 2H2O (l)

A 25.0 cm3 portion of 0.100 mol dm−3 sodium hydroxide solution required 12.80 cm3 of the solution of the diprotic acid for complete neutralisation.
What is the concentration of H2A in mol dm−3?

  • 2.56 × 10−2

  • 9.77 × 10−2

  • 1.95 × 10−1

  • 3.91 × 10−1

Choose your answer

Did this page help you?

8
Sme Calculator1 mark

In which compound is the oxidation number of nitrogen +5?

  • Ca(NO3)2

  • Mg3N2

  • N2O3

  • NaNO2

Choose your answer

Did this page help you?

91 mark

Which reaction is not a redox reaction?

  • 4KClO3 (s) → 3KClO4 (s) + KCl (s)

  • 2HCl (aq) + Ba(OH)2 (aq) → BaCl2 (aq) + 2H2O (l)

  • Zn (s) + CuSO4 (aq) → ZnSO4 (aq) + Cu (s)

  • Cl2 (g) + H2O (l) → HCl (aq) + HClO (aq)

Choose your answer

Did this page help you?

101 mark

In which reaction is the copper species acting as an oxidising agent?

  •  Cu2+ + 2Ag → 2Ag+ + Cu

  • 2Cu++ O2– → Cu2O

  • 3Cu + O2 → Cu2O + CuO

  • Cu + Hg2+ → Hg + Cu2+

Choose your answer

Did this page help you?

11
Sme Calculator1 mark

Two half‐equations for a reaction are shown.

Cu → Cu2+ + 2e−

NO3− + 4H+ + 3e− → NO + 2H2O

What is the overall ionic equation for this reaction?

  • Cu + Nstraight O subscript 3 superscript minus+ 4H+→ Cu2+ + NO + 2H2O

  • 2Cu + Nbegin mathsize 16px style O subscript 3 to the power of minus sign end style+ 4H+→ 2Cu2+ + NO + 2H2O

  • 3Cu + 2Nstraight O subscript 3 superscript minus+ 8H+→ 3Cu2+ + 2NO + 4H2O

  • 6Cu + 2Nstraight O subscript 3 superscript minus+ 8H+→ 6Cu2+ + 2NO + 4H2O

Choose your answer

Did this page help you?

12
Sme Calculator1 mark

A titre of 13.25 cm3 was obtained using a 50 cm3 burette.

What is the percentage uncertainty in the titre?

[Each reading of the burette has an uncertainty of ±0.05 cm3]

  • ±0.38%

  • ±0.75%

  • ±1.5%

  • ±7.5%

Choose your answer

Did this page help you?

13a
Sme Calculator1 mark
a)

A pellet of sodium hydroxide has a mass of 0.700 g.

Some pellets were dissolved to make 350 cm3 of 0.25 mol dm–3 solution.

[Mr value: NaOH = 40]

How many pellets were dissolved?

  • 4

  • 5

  • 8

  • 125

Choose your answer

13b
Sme Calculator1 mark
b)

25.0 cm3 of the sodium hydroxide solution prepared in (a) was placed in a conical flask and titrated with sulfuric acid.

2NaOH + H2SO4 → Na2SO4 + 2H2O

Calculate the number of moles of sulfuric acid that reacted.

  • 0.0031

  • 0.0063

  • 0.013

  • 0.044

Choose your answer

13c1 mark
c)
Phenolphthalein indicator was used for the titration in (b). 
What was the colour change at the endpoint?

  • colourless → pink

  • pink → colourless

  • orange → yellow

  • yellow → orange

Choose your answer

Did this page help you?