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Worksheets

ELECTROCHEMISTRY

Total questions: 25

Worksheet time: 25mins

Name
Class
Date
1.

Diagram shows an electrolysis cell.

Which of the substances cause the bulb to light up when electricity passes through it?

a)

Ethanol

b)

Dilute ethanoic acid

c)

Solid lead(II) bromide

d)

Tetrachloromethane

2.

What are the products formed at the anode and the cathode during the electrolysis of molten magnesium oxide using carbon electrodes?

a)

Anode: Oxygen

Cathode: Magnesium

b)

Anode: Magnesium

Cathode: Oxygen

c)

Anode: Hydrogen

Cathode: Oxygen

d)

Anode: Oxygen

Cathode: Hydrogen

3.

Table shows information about three chemical cells.

What is the possible potential difference of the chemical cell when metal Z is paired with W ?

a)

0.3 V

b)

1.2 V

c)

1.5 V

d)

2.1 V

4.

Diagram shows the electrolysis of concentrated copper(II) chloride solution using carbon as electrodes.

Which of the followings is the correct half equations represents the reactions at the anode?

a)

4OH- → 2H2O + O2 + 4e

b)

2Cl- → Cl2 + 2e

c)

Cu → Cu2+ + 2e

d)

Cu2+ + 2e → Cu

5.

Diagram

shows the apparatus set-up for the electrolysis of 1.0 mol dm -3 sodium chloride solution using carbon electrodes.Which of the following are the observation for the electrolysis process shown in Diagram?


a)

Grey solid deposited on electrode B

b)

Colourless gas is released at electrode B

c)

Carbon electrode A becomes thinner

d)

Greenish yellow gas is released at electrode A

6.

Molten X is electrolysed using carbon electrodes. After 10 minutes, a brown solid is deposited on the cathode and a brown gas is released at the anode. What is molten X?

a)

Lead(II) chloride

b)

Lead(II) bromide

c)

Copper(II) chloride

d)

Copper(II) bromide

7.

Table shows the results of the electrolysis of molten lead (II) bromide.


The ammeter only shows reading when solid lead (II) bromide, PbBr2 is completely melted. Which of the following explains the observation?

a)

Bromide ions receive electrons to form bromine gas

b)

Lead (II) ions donate electrons to produce lead metal

c)

In the solid state, bromide and lead (II) ions are in fixed position

d)

Electrical conductivity occurs throughout

the whole experiment

8.

Diagram shows an electrolysis of dilute sulphuric acid.

What could be gas X and the half-equation occurring at the cathode?

a)

Carbon dioxide, C + O2 → CO2

b)

Hydrogen, 2H+ + 2e —>H2

c)

Oxygen, 4OH- → H2O + O2 + 4e-

d)

Sulphur dioxide, SO4 2- → SO2 + O2 + 2e-

9.

Diagram shows an apparatus set-up for a chemical cell. What can you observed from this experiment?

a)

oxygen gas is liberated at the copper plate

b)

Magnesium electrode becomes thinner

c)

Colourless solution turns to brown

d)

Electron flows from magnesium to the copper plate

10.

Chemical cells convert

a)

mechanical energy in to electrical energy

b)

potential energy in to electrical energy

c)

electrical energy in to chemical energy

d)

chemical energy in to electrical energy

11.

What is an anode?

a)

It is the electrode where oxidation takes place.

b)

It is the electrode where reduction takes place.

c)

It is an aqueous solution containing an electrode.

d)

It is the salt bridge that connects half-cells.

12.

Electrons always flow from

a)

cathode to anode

b)

anode to cathode

13.

Electrochemistry is

a)

Study of electron in atom

b)

Study of electricity in molecules

c)

The relationship between chemical reactions and electricity

d)

the study of electrons moving from one atom to another

14.

State one functions of salt bridge

a)

to maintain the movement of electron

b)

to allowing electron to flow and complete the circuit

c)

to separate two electrolyte

d)

to allowing movement of ion to complete the circuit

15.

What happens at the positive terminal in a voltaic cell and in an electrolytic cell?

a)

A

b)

B

c)

C

d)

D

16.

What are product produced at positive/negative terminal during electrolysis of molten NaCI?

a)

A

b)

B

c)

C

d)

D

17.

What is the name of the positive terminal in an electrolytic cell?

a)

cathode

b)

anode

18.
In electrolytic cell which its electrolyte is copper (II) sulphate, copper are used as electrodes. What is the product at the anode?
a)
Oxygen gas and water
b)
Copper metal
c)
Copper (II) ions
d)
Hydrogen gas
19.
Which are used for electroplating of a metal spoon with copper?
a)
I and II
b)
I and III
c)
II and III
d)
I, II and III
20.
What happens when molten NaCI is electrolysed in electrolytic cell?
a)
Chlorine is produced at positive electrode
b)
Sodium ions lose electrons at negative electrode
c)
Electrons flow through liquid from -ve electrode to +ve electrode
d)
Oxidation occurs at -ve electrode and reduction at +ve electrode
21.
Which statement correctly describes the 2 electrodes?
a)
The anode is negative and the cathode is positive
b)
The anode and cathode are both positive
c)
The anode is positive and the cathode is negative
d)
The anode and cathode are both negative.
22.
Dilute aqueous zinc chloride is electrolysed using platinum electrodes. What are the products at the electrodes?
a)
anode: chlorine
cathode: hydrogen
b)
anode: hydrogen
cathode: oxygen
c)
anode: oxygen
cathode: hydrogen
d)
cathode: zinc
cathode: oxygen
23.
Below shows a cell diagram for voltaic cell. Which of the following is FALSE?
a)
Electrons flow from anode to cathode
b)
Oxidation happens in anode
c)
Copper undergo reduction to form copper ions
d)
Zinc undergo oxidation to form Zinc ions
24.
a)

a

b)

b

c)

c

d)

d

25.

The overall reaction in an electrochemical cell is

Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s)

As the reaction in this cell takes place, the

a)

mass of the Zn electrode decreases

b)

Zn2+concentration remains the same

c)

mass of the Cu electrode decreases

d)

Cu2+ concentration remains the same