Chemistry - Electrochemistry
Exam Duration: 60 Mins Total Questions : 30
The life span of aDaniell cell may be increased by
- (a)
Large Zn electrode
- (b)
Large Cu electrode
- (c)
Lowering the temperature
- (d)
Lowering the concentrations
In a hydrogen-oxygen fuel cell, combustion of hydrogen occurs to
- (a)
Generate heat
- (b)
Create potential difference between the two electrodes
- (c)
Produce high purity water
- (d)
Remove adsorbed oxygen from electrode surfaces
The sacrificial anode protects iron or ships, underground pipelines etc; from rusting, a process is known as cathodic protection, which one of the following metal cannot be used as sacrificial anode?
- (a)
Tin
- (b)
Zinc
- (c)
Magnesium
- (d)
Aluminium
The depolarization in a primary cell is used for the purpose of
- (a)
Increasing the life of the cell
- (b)
Increasing the emf of the cell
- (c)
Removing the hydrogen collected at one of the plates
- (d)
Removing the dipoles from the electrolytes
A smuggler could not carry gold by depositing iron on the gold surface, because
- (a)
Gold has lower standard reduction potential than iron
- (b)
Gold has higher standard reduction potential than iron.
- (c)
Iron rusts
- (d)
Gold in denser
Consider the following statements
1. The conductivity of electrolyte increases with a rise in temperature.
2. The voltmeter is used in the process of electrolysis.
3. Electrolysis of water is also called hydrolysis.
- (a)
1, 2 and 3
- (b)
1 and 2
- (c)
2 and 3
- (d)
3 only
When two plates of different metals are placed in an electrolyte, the developed emf between them depends on
- (a)
The type of electrolyte
- (b)
Distance between the plates
- (c)
The position of the two metals in the electrochemical series.
- (d)
All of the above
The conduction of electricity through the electrolyte solution is due to
- (a)
Movement of molecule of electrolyte
- (b)
Movement of ions of electrolyte
- (c)
Movement of separate atom
- (d)
Movement of particles of the solvent
Consider the following statements regarding a motor car battery.
1. The voltage is usually 12V.
2. The electrolyte used is hydrochloric acid.
3. Electrodes are lead and copper.
4. Capacity is expressed in ampere-hours.
- (a)
1 and 2
- (b)
2 and 3
- (c)
3 and 4
- (d)
1 and 4
Consider the following statements
1. Galvanic cell converts chemical energy into electrical energy.
2. In a galvanic cell, the electron flow from anode to the cathode through the external circuit.
3.Galvanic cell converts metal from its elemental state to the combined state.
- (a)
Only 1
- (b)
Only 2
- (c)
1 and 2
- (d)
1, 2 and 3
When an acid cell is a charged, then
- (a)
Voltage of cell increases
- (b)
Resistance of cell increases
- (c)
Electrolyte of cell dilutes
- (d)
None of the above
Thr advantage of using fuel cell in a motor car could be
- (a)
Low initial cost
- (b)
Emission less operation
- (c)
Lightweight
- (d)
Freedom from refuelling
Which one among the following metals is more reactive than hydrogen?
- (a)
Mercury
- (b)
Copper
- (c)
Silver
- (d)
Tin
Which of the following statements about the commonly used automobile battery are true?
1. It is the usual a lead-acid battery.
2. It has six cells with a potential of 2V each.
3. Its cells work as galvanic cells while discharging power.
4. Its cells work as electrolytic cells while recharging.
- (a)
1, 2, 3 and 4
- (b)
1, 2 and 3
- (c)
2 and 4
- (d)
3 and 4
Match the Column I with the Column II.
Column I | Column II |
A. Primary | 1. Reaction between Zn and Cu ions to produce an electric current |
B. Battery | 2. Change of chemical energy to electrical energy |
C. Electrochemical cell | 3. Lead storage battery |
D. Daniell celll | 4. Leclanche cell |
- (a)
A B C D 4 3 2 1 - (b)
A B C D 3 2 1 4 - (c)
A B C D 2 1 4 3 - (d)
A B C D 1 4 3 2
Assertion (A) For a galvanic cell, oxidation takes place at anode and reduction at the cathode.
Reason (R) Electrons in the external circuit move from the anode to the cathode.
- (a)
Both A and R are true and R is the correct explanation of A
- (b)
Both A and R are true, but R is not the correct explanation of A
- (c)
A is true, but R is false
- (d)
A is false, but Ris true
Consider the following statements The electrochemical series helps
1. In extraction of metals
2. In protecting the metal from corrosion
3. In comparing the reactivity of metals
- (a)
Only 1
- (b)
Only 2
- (c)
2 and 3
- (d)
1, 2 and 3
When items or jewellery made of metals such as copper or nickel are placed in a solution having a salt of gold, a thin film of gold is deposited by
- (a)
Cooling to below 0\(^{o}\) C
- (b)
Heating above 100\(^{o}\) C
- (c)
Passing an electric current
- (d)
Just keeping it for 10 min
In an electrochemical cell that functions as a voltaic cell
- (a)
Electrons move from the cathode to the anode
- (b)
Electrons move through a salt-bridge
- (c)
Electrons can move either from the cathode to the anode or from the anode to the cathode
- (d)
Reduction occurs at the cathode
When a lead storage battery is discharged
- (a)
So2 is evolved
- (b)
Lead id formed
- (c)
Lead sulphate is formed
- (d)
Sulphuric acid is consumed
Anode mud is a
- (a)
Mixture of impure metals like Fe
- (b)
So2 gas
- (c)
Mixture of Ag, Au, Pt
- (d)
None of the above
On the basis of position in the electrochemical series, the metal which does not displace hydrogen from water and acid is
- (a)
AI
- (b)
Pb
- (c)
Ba
- (d)
Hg
A conductivity cell is platinised
- (a)
To prolong its service
- (b)
To avoid temperature effect
- (c)
To avoid polarisation effect
- (d)
None of the above
Assertion (A) Copper metal with HCI liberates hydrogen.
Reason (R) Hydrogen is present above Cu in the reactivity series.
- (a)
Both A and R are True and R is the correct explanation of A
- (b)
Both A and R are true, but R is not the correct explanation of A
- (c)
A is true, but R is false
- (d)
A is false, but R is true
Which one of the following pairs of materials serves as. electrodes in chargeable batteries commonly used in devices such as torchlights, electric shavers etc?
- (a)
Nickel and cadmium
- (b)
Zinc and carbon
- (c)
Lead peroxide and lead
- (d)
Iron and cadmium
Galvanised iron sheets are protected from rusting due to presence of a layer of
- (a)
Lead
- (b)
Chromium
- (c)
Zinc
- (d)
Tin
Aluminium surfaces are often 'anodised'. This means the deposition of a layer of
- (a)
Chromium oxide
- (b)
Aluminium oxide
- (c)
Nickel oxide
- (d)
Zinc oxide
Consider the following statements
1. Albo iron does not rust in a vacuum because air is necessary for rusting.
2. Rust is faster in sea water because of dissolved salts.
- (a)
Only 1
- (b)
Only 2
- (c)
1 and 2
- (d)
None of these
The source of electrical energy On the Appolo moon flights was
- (a)
A generator set
- (b)
H2 -O2 fuel cell
- (c)
Ni-Cd cell
- (d)
Lead storage batteries
The depolarizer used id dry cell is
- (a)
MnO2
- (b)
NH4 CI
- (c)
Carbon
- (d)
ZnCI2