# Electrochemistry Test 6

Total Questions:50 Total Time: 75 Min

Remaining:

## Questions 1 of 50

Question:When electric current is passed through a cell having an electrolyte, the positive ions move towards the cathode and the negative ions towards the anode. If the cathode is pulled out of the solution

The positive and negative ions will move towards the anode

The positive ions will start moving towards the anode, the negative ions will stop moving

The negative ions will continue to move towards the anode and the positive ions will stop moving

The positive and negative ions will start moving randomly

## Questions 2 of 50

Question:A cell from the following which converts electrical energy into chemical energy

Dry cell

Electrochemical cell

Electrolytic cell

None of these

## Questions 3 of 50

Question:In the cell $$Zn\,\,|\,\,Z{n^{2 + }}\,\,||\,\,C{u^{2 + }}\,\,|\,\,Cu,$$ the negative electrode is

$$Cu$$

$$C{u^{2 + }}$$

$$Zn$$

$$Z{n^{2 + }}$$

## Questions 4 of 50

Question:The molar conductances of $$NaCl,\,HCl$$ and $$C{H_3}COONa$$ at infinite dilution are 126.45, 426.16 and $$91\,oh{m^{ - 1}}\,c{m^2}\,mo{l^{ - 1}}$$ respectively. The molar conductance of $$C{H_3}COOH$$ at infinite dilution is

$$201.28\,oh{m^{ - 1}}\,c{m^2}\,mo{l^{ - 1}}$$

$$390.71\,oh{m^{ - 1}}c{m^2}\,mo{l^{ - 1}}$$

$$698.28\,oh{m^{ - 1}}\,c{m^2}\,mo{l^{ - 1}}$$

$$540.48\,oh{m^{ - 1}}c{m^2}\,mo{l^{ - 1}}$$

## Questions 5 of 50

Question:The electrodes of a conductivity cell are $$3\,cm$$ apart and have a cross-sectional area of $$4\,c{m^2}$$. The cell constant of the cell (in $$c{m^{ - 1}}$$) is

$$4 \times 3$$

$$4/3$$

$$3/4$$

$$9/4$$

## Questions 6 of 50

Question:In a hydrogen – oxygen fuel cell, combustion of hydrogen occurs to

Produce high purity water

Create potential difference between the two electrodes

Generate heat

Remove adsorbed oxygen from electrode surfaces

## Questions 7 of 50

Question:$${\lambda _{ClC{H_2}COONa}} = 224\,oh{m^{ - 1}}c{m^2}gme{q^{ - 1}}$$, $${\lambda _{NaCl}} = 38.2\,oh{m^{ - 1}}c{m^2}gme{q^{ - 1}}$$, $${\lambda _{HCl}} = 203\,oh{m^{ - 1}}c{m^2}gme{q^{ - 1}}$$,What is the value of $${\lambda _{ClC{H_2}COOH}}$$

$$288.5\;oh{m^{ - 1}}c{m^2}gme{q^{ - 1}}$$

$$289.5\;oh{m^{ - 1}}c{m^2}gme{q^{ - 1}}$$

$$388.5\;oh{m^{ - 1}}c{m^2}gme{q^{ - 1}}$$

$$59.5\;oh{m^{ - 1}}c{m^2}gme{q^{ - 1}}$$

## Questions 8 of 50

Question:The factor which is not affecting the conductivity of any solution is

Dilution

Nature of electrolyte

Temperature

None of these

## Questions 9 of 50

Question:Specific conductance of 0.1 m nitric acid is $$6.3 \times {10^{ - 2}}\,oh{m^{ - 1}}c{m^{ - 1}}$$. The molar conductance of solution is

630 $$oh{m^{ - 1}}c{m^2}mol{e^{ - 1}}$$

315 $$oh{m^{ - 1}}c{m^2}mol{e^{ - 1}}$$

100 $$oh{m^{ - 1}}c{m^2}mol{e^{ - 1}}$$

6300 $$oh{m^{ - 1}}c{m^2}mol{e^{ - 1}}$$

63.0 $$oh{m^{ - 1}}c{m^2}mol{e^{ - 1}}$$

## Questions 10 of 50

Question:Which one is not a conductor of electricity

$$NaCl$$(aqueous)

$$NaCl$$ (solid)

$$NaCl$$ (molten)

$$Ag$$ metal

## Questions 11 of 50

Question:Solid sodium chloride is bad conductor of electricity because

It contains only molecules

It does not possess ions

The ions present in it are not free to move

It does not contain free molecules

## Questions 12 of 50

Question:When $$Zn$$ piece is kept in $$CuS{O_4}$$ solution, the copper get precipitated due to standard potential of zinc is

> copper

< copper

> sulphate

< sulphate

## Questions 13 of 50

Question:Which of the following metal does not react with the solution of copper sulphate

$$Mg$$

$$Fe$$

$$Zn$$

$$Ag$$

## Questions 14 of 50

Question:The reaction $$Z{n^{2 + }} + 2{e^ - } \to Zn$$ has a standard potential of $$- 0.76\,V$$. This means

$$Zn$$ can't replace hydrogen from acids

$$Zn$$ is a reducing agent

$$Zn$$ is a oxidising agent

$$Z{n^{2 + }}$$is a reducing agent

## Questions 15 of 50

Question:$$2{H^ + }\,(aq) + 2{e^ - }\, \to \,{H_2}\,(g).$$The standard electrode potential for the above reaction is (in volts)

0

1

1

None of these

## Questions 16 of 50

Question:A cell constructed by coupling a standard copper electrode and a standard magnesium electrode has emf of 2.7 volts. If the standard reduction potential of copper electrode is + 0.34 volt that of magnesium electrode is

+ 3.04 volts

3.04 volts

+ 2.36 volts

2.36 volts

## Questions 17 of 50

Question:When $$E_{A{g^ + }/Ag}^o = 0.8$$volt and $$E_{Z{n^{2 + }}/Zn}^o = - 0.76\,$$ volt, which of the following is correct

$$A{g^ + }$$ can be reduced by $${H_2}$$

$$Ag$$ can oxidise $${H_2}$$ into $${H^ + }$$

$$Z{n^{2 + }}$$ can be reduced by $${H_2}$$

$$Ag$$ can reduce $$Z{n^{2 + }}$$ ion

## Questions 18 of 50

Question:Amongst the following electrodes the one with zero electrode potential is

Calomel electrode

Standard hydrogen electrode

Glass electrode

Gas electrode

## Questions 19 of 50

Question:Which of the following is correct expression for electrode potential of a cell

$$E = {E^o} - \frac{{RT}}{{nF}}\,\ln \,\frac{{{\rm{[product]}}}}{{{\rm{[reactant]}}}}$$

$$E = {E^o} + \frac{{RT}}{F}\,\ln \,\frac{{{\rm{[product]}}}}{{{\rm{[reactant]}}}}$$

$$E = {E^o} - \frac{{RT}}{{nF}}\,\ln \,\frac{{{\rm{[reactant]}}}}{{{\rm{[product]}}}}$$

$$E = - \frac{{RT}}{F}\ln \,\frac{{{\rm{[product]}}}}{{[{\rm{reactant]}}}}$$

## Questions 20 of 50

Question:Calculate standard free energy change for the reaction $$\frac{1}{2}Cu(s) + \frac{1}{2}C{l_2}(g)$$?$$\frac{1}{2}C{u^{2 + }} + C{l^ - }$$ taking place at $${25^o}C$$ in a cell whose standard e.m.f. is 1.02 volts

98430 J

98430 J

96500 J

49215 J

## Questions 21 of 50

Question:The emf of a Daniel cell at 298K is $${E_1}$$ $$Zn|\mathop {ZnS{O_4}}\limits_{(0.01\,\,M)} ||\mathop {CuS{O_4}}\limits_{(1.0\,\,M)} |Cu$$ when the concentration of $$ZnS{O_4}$$ is 1.0 M and that of $$CuS{O_4}$$ is 0.01 M, the emf changed to $${E_2}$$. What is the relationship between $${E_1}$$ and $${E_2}$$

$${E_2} = 0 \ne {E_1}$$

$${E_1} > {E_2}$$

$${E_1} < {E_2}$$

$${E_1} = {E_2}$$

## Questions 22 of 50

Question:The oxidation potentials of following half-cell reactions are given $$Zn \to Z{n^{2 + }} + 2{e^ - };{E^o} = 0.76\,\,V$$,$$Fe \to F{e^{2 + }} + 2{e^ - };{E^o} = 0.44\,\,V$$ what will be the emf of cell, whose cell-reaction is $$F{e^{2 + }}(aq) + Zn \to Z{n^{2 + }}(aq) + Fe$$

1.20 V

+ 0.32 V

0.32 V

+ 1.20 V

## Questions 23 of 50

Question:The $${E^o}$$ for half cells $$Fe/F{e^{2 + }}$$ and $$Cu/C{u^{2 + }}$$ are – 0.44 V and + 0.32 V respectively. Then

$$C{u^{2 + }}$$oxidises $$Fe$$

$$C{u^{2 + }}$$oxidises $$F{e^{2 + }}$$

$$Cu$$ oxidises $$F{e^{2 + }}$$

$$Cu$$ reduces $$F{e^{2 + }}$$

## Questions 24 of 50

Question:What will be the emf for the given cell $$Pt|{H_2}({P_1})|{H^ + }_{(aq)}||{H_2}({P_2})|Pt$$

$$\frac{{RT}}{f}\log \frac{{{P_1}}}{{{P_2}}}$$

$$\frac{{RT}}{{2f}}\log \frac{{{P_1}}}{{{P_2}}}$$

$$\frac{{RT}}{f}\log \frac{{{P_2}}}{{{P_1}}}$$

None of these

## Questions 25 of 50

Question:What is the potential of a cell containing two hydrogen electrodes the negative one in contact with $${10^{ - 8}}$$M $${H^ + }$$and positive one in contact with 0.025 M $${H^ + }$$

0.18 V

0.28 V

0.38 V

0.48 V

## Questions 26 of 50

Question:Will $$F{e_{(s)}}$$be oxidised to $$F{e^{2 + }}$$ by the reaction with 1 M $$HCl$$$$({E^o}$$ for $$Fe/F{e^{2 + }}$$= + 0.44 V)

Yes

No

May be

Can’t say

## Questions 27 of 50

Question:What is wrongly stated about electrochemical series

It is the representation of element in order of increasing or decreasing standard electrode reductional potential

It does not compare the relative reactivity of metals

It compares relative strengths of oxidising agents

$${H_2}$$ is centrally placed element

## Questions 28 of 50

Question:Which of the following statements is true for fuel cells

They are more efficient

They are free from pollution

They run till reactants are active

All of these

## Questions 29 of 50

Question:What is the potential of a half-cell consisting of zinc electrode in 0.01m $$ZnS{O_4}$$ solution at $${258^o}C$$ $$({E^o} = 0.763\,V)$$

0.8221 V

8.221 V

0.5282 V

9.232 V

## Questions 30 of 50

Question:The e.m.f. of the cell $$Ag|A{g^ + }(0.1M)||A{g^ + }(1M)|Ag$$ at 298 K is

0.0059 V

0.059 V

5.9 V

0.59 V

## Questions 31 of 50

Question:The e.m.f. of the cell $$Zn|Z{n^{2 + }}(0.01M)||F{e^{2 + }}(0.001M)|Fe$$ at 298 K is 0.2905 then the value of equilibrium for the cell reaction is

$$\frac{{0.32}}{{{e^{0.0295}}}}$$

$$\frac{{0.32}}{{{{10}^{0.0295}}}}$$

$$\frac{{0.26}}{{{{10}^{0.0295}}}}$$

$$\frac{{0.32}}{{{{10}^{0.0591}}}}$$

## Questions 32 of 50

Question:Aluminium displaces hydrogen from dilute HCl whereas silver does not. The e.m.f. of a cell prepared by combining $$Al/A{l^{3 + }}$$ and $$Ag/A{g^ + }$$is 2.46 V. The reduction potential of silver electrode is $$+ 0.80\;V$$. The reduction potential of aluminium electrode is

$$+ 1.66\;V$$

$$- 3.26\,V$$

$$3.26\;V$$

$$- 1.66\;V$$

## Questions 33 of 50

Question:Strong electrolytes are those which

Conduct electricity

Dissociate into ions at high dilution

Completely dissociate into ions at all dilutions

## Questions 34 of 50

Question:In aqueous solution, strong electrolytes

Are partially ionized

Do not ionize

Ionise almost completely

Form polymers

## Questions 35 of 50

Question:The addition of a polar solvent to a solid electrolyte results in

Polarization

Association

Ionization

Non-liberation of heat

## Questions 36 of 50

Question:During the electrolysis of fused $$NaCl,$$ which reaction occurs at anode

Chloride ions are oxidized

Chloride ions are reduced

Sodium ions are oxidized

Sodium ions are reduced

## Questions 37 of 50

Question:During electrolysis, the species discharged at cathode are

Ions

Cation

Anion

All of these

## Questions 38 of 50

Question:Electrolysis of molten anhydrous calcium chloride produces

Calcium

Phosphorus

Sulphur

Sodium

## Questions 39 of 50

Question:If the current is passed into the solution of an electrolyte

Anions move towards anode, cations towards cathode

Anions and cations both move towards anode

Anions move towards cathode, cations towards anode

No movement of ions takes place

## Questions 40 of 50

Coulomb

Coulomb $$mol{e^{ - 1}}$$

Coulomb $$Se{c^{ - 1}}$$

Ampere

## Questions 41 of 50

Question:According to the first law of Faraday, the weight of a substance discharge at the electrode is

$$W = ZQ$$

$$W = eF$$

$$W = \frac{Z}{F}\,It$$

$$W = ZI$$

## Questions 42 of 50

Question:When 0.04 faraday of electricity is passed through a solution of $$CaS{O_4}$$, then the weight of $$C{a^{2 + }}$$ metal deposited at the cathode is

0.2 gm

0.4 gm

0.6 gm

0.8 gm

## Questions 43 of 50

Question:Coulomb is equal to

ampere ´ second

ampere ´ minute

watt ´ second

volt ´ second

## Questions 44 of 50

Question:The energy required to release 1 electron from $$H{e^ + }$$is…….

+ 54.4 eV

13.6 eV

+ 27.2 eV

Cannot be predicted

## Questions 45 of 50

Question:The aqueous solution of which of the following decomposes on passing electric current

Canesugar

Urea

Methanol

Potassium iodide

## Questions 46 of 50

Question:The number of Faradays needed to reduce 4 gram equivalents of $$C{u^{ + + }}$$ to $$Cu$$ metal will be

1

2

2-Jan

4

## Questions 47 of 50

Is a numerical constant

Depends on equivalent

Depends upon the current passed

Depends on the number of electrons

## Questions 48 of 50

Question:If 0.5 amp current is passed through acidified silver nitrate solution for 10 minutes. The mass of silver deposited on cathode, is (eq. wt. of silver nitrate = 108)

0.235 g

0.336 g

0.536 g

0.636 g

## Questions 49 of 50

Question:A galvanic cell is set up from a zinc bar weighing 50g and 1.0litre, 1.0M, $$CuS{O_4}$$ solution. How long would the cell run, assuming it delivers a steady current of 1.0 ampere

48 hrs

41 hrs

21 hrs

1 hr

## Questions 50 of 50

Question:On passing electric current through molten aluminium chloride, 11.2 litre of $$C{l_2}$$ is liberated at NTP at anode. The quantity of aluminium deposited at cathode is (at. wt. of Al = 27)