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1.1 Oxidation & Reduction (C)

Total questions: 25

Worksheet time: 25mins

Name
Class
Date
1.

Which of the following statements refers to an oxidation process?

a)

Hydrogen is added to ethene

b)

Oxygen is removed from carbon dioxide

c)

Chlorine accepts electrons

d)

Increase in the oxidation number of magnesium metal

2.

Which of these equations represents a redox reaction?

a)

Ca(HCO3)2 --> CaCO3 + H2O + CO2

b)

CH3COOH + NaOH --> CH3COONa + H2O

c)

Zn + 2FeCl3 --> ZnCl2 + 2FeCl2

d)

NaCl + AgNO3 --> AgCl + NaNO3

3.

What is the oxidation number of chlorine in ClO3- ?

a)

-1

b)

+1

c)

-1

d)

+5

4.

What are the oxidation numbers of manganese in the manganese compounds shown below?

a)

A

b)

B

c)

C

d)

D

5.

Which of the following is the oxidising agent in the experiment shown the diagram?

a)

Iron(II) ion

b)

Sulphate ion

c)

Iron

d)

Bromine

6.

Which of the following statements is not true when zinc powder is added to dilute hydrochloric acid?

a)

Zinc is oxidised

b)

Chloride ion acts as an oxidising agent

c)

Hydrogen ion is reduced

d)

Electrons are transferred in the reaction

7.

The table shows four chemical changes. Which changes involve donation of electrons?

a)

P and Q

P and R

Q and S

R and S

b)

P and R

c)

Q and S

d)

R and S

8.

The diagram shows two metals P and Q connected together in a liquid jelly. Metal Q is more electropositive than metal P. Which of the following statements is true?

a)

P is oxidised

b)

Q is reduced

c)

The oxidation number of metal P has increased

d)

The oxidation number of metal Q has increased

9.

A mixture of magnesium oxide, copper(II) oxide and zinc powder is heated in a crucible until no further changes are observed. After heating, the mixture contains:

a)

magnesium, copper(II) oxide and zinc

b)

magnesium oxide, copper and zinc oxide

c)

magnesium oxide, copper(II) oxide and zinc

d)

magnesium, copper and zinc oxide

10.

In an electrochemical cell, tin becomes a negative terminal when it is connected to

a)

aluminium

b)

lead

c)

magnesium

d)

zinc

11.

Oxidation involves

a)

gaining electrons; gaining oxygen

b)

losing electrons; losing oxygen

c)

gaining electrons; losing oxygen

d)

losing electrons; gaining oxygen

12.
Reduction involves 
a)
gaining electrons; gaining oxygen
b)
losing electrons; losing oxygen
c)
gaining electrons, losing oxygen
d)
losing electrons; gaining oxygen
13.

Identify the substance that is oxidised in the reaction between carbon and zinc oxide.

C + 2ZnO → CO2 + 2Zn

a)

C

b)

ZnO

c)

CO2

d)

Zn

14.

Identify the substance that is reduced in the reaction between hydrogen and iron(II) oxide.

H2 + FeO → H2O + Fe

a)

H2

b)

FeO

c)

H2O

d)

Fe

15.

Identify the substance that is oxidised in the reaction between aluminium and chromium(III) ion.

Al + Cr3+ → Al3+ + Cr

a)

Al

b)

Cr3+

c)

Al3+

d)

Cr

16.

Identify the substance that is reduced in the reaction between copper(II) ion and magnesium.

Cu2+ + Mg → Cu + Mg2+

a)

Cu2+

b)

Mg

c)

Cu

d)

Mg2+

17.

Identify the oxidising agent in the reaction between copper(II) oxide and hydrogen.

CuO + H2 → Cu + H2O

a)

CuO

b)

H2

c)

Cu

d)

H2O

18.

Identify the reducing agent in the reaction between sulfuric acid and zinc.

H2SO4 + Zn → H2 + ZnSO4

a)

H2SO4

b)

Zn

c)

H2

d)

ZnSO4

19.

Identify the oxidising agent in the reaction between iron(II) chloride and zinc.

2FeCl3 + 3Zn → 2Fe + 3ZnCl2

a)

FeCl3

b)

Zn

c)

Fe

d)

ZnCl2

20.

Identify the reducing agent in the reaction between aluminium and iron(III) oxide.

Al + Fe2O3 → Al2O3 + Fe

a)

Al

b)

Fe2O3

c)

Al2O3

d)

Fe

21.

What is the colour change of acidified KMnO4 solution when it is used as an oxidising agent?

a)

from colourless to brown

b)

from brown to colourless

c)

from purple to colourless

d)

from colourless to purple

22.

When sulfur dioxide gas is passed through an acidified aqueous solution of X, the solution changes from orange to green. What is X?

a)

methyl orange

b)

potassium dichromate(VI)

c)

potassium iodide

d)

potassium manganate(VII)

23.

An aqueous solution of potassium iodide turns from colourless to brown. What happens to the iodide ions?

a)

Iodide ions are oxidised due to gain of electrons.

b)

Iodide ions are oxidised due to loss of electrons.

c)

Iodide ions are reduced due to gain of electrons.

d)

Iodide ions are reduced due to loss of electrons.

24.

Aqueous potassium iodide is a reducing agent and can be used as a test for an oxidising agent.

a)

True

b)

False

25.

Acidified potassium manganate(VII) solution and acidified potassium dichromate(VI) solution are both oxidising agents used to test for a reducing agent.

a)

True

b)

False