# Electrochemistry Test 1

Total Questions:50 Total Time: 75 Min

Remaining:

## Questions 1 of 50

Question:The specific conductance of a 0.1 N KCl solution at $${23^o}C$$ is $$0.012\,oh{m^{ - 1\,}}c{m^{ - 1}}$$. The resistance of cell containing the solution at the same temperature was found to be 55 ohm. The cell constant will be

$$0.142\,c{m^{ - 1}}$$

$$0.66\,c{m^{ - 1}}$$

$$0.918\,c{m^{ - 1}}$$

$$1.12\,c{m^{ - 1}}$$

## Questions 2 of 50

Question:Which of the following reactions occurs at the cathode of a common dry cell

$$Mn\, \to \,M{n^{2 + }} + 2{e^ - }$$

$$2Mn{O_2} + Z{n^{2 + }} + 2{e^ - }\, \to \,\,ZnM{n_2}{O_4}$$

$$2Zn{O_2} + M{n^{2 + }} + 2{e^ - }\, \to \,\,MnZ{n_2}{O_4}$$

$$Zn\, \to \,Z{n^{2 + }} + 2{e^ - }$$

## Questions 3 of 50

Question:In $$Cu - Zn$$ cell

Reduction occurs at the copper cathode

Oxidation occurs at the copper cathode

Reduction occurs at the anode

Chemical energy is converted to light energy

## Questions 4 of 50

Question:The standard cell potential of $$Zn|Z{n^{2 + }}_{(aq)}||C{u^{2 + }}_{(aq)}|Cu$$ cell is 1.10 V. The maximum work obtained by this cell will be

106.15 kJ

212.30 kJ

318.45 kJ

424.60 kJ

## Questions 5 of 50

Question:The relationship between standard reduction potential of cell and equilibrium constant is shown by

$$E_{cell}^0 = \frac{n}{{0.059}}\log {K_c}$$

$$E_{cell}^0 = \frac{{0.059}}{n}\log {K_c}$$

$$E_{cell}^0 = 0.059\,n\,\log {K_c}$$

$$E_{cell}^0 = \frac{{\log {K_c}}}{n}$$

## Questions 6 of 50

Question:Consider the Galvanic cell $$\,Z{n^\Theta }|ZnS{O_4}||CuS{O_4}|C{u^ \oplus }$$ the reaction at cathode is

$$Z{n^2}^ + + 2{e^ - } \to Zn$$

$$C{u^{2 + }} + 2{e^ - } \to Cu$$

$$C{u^{2 + }} + Zn \to Cu + Z{n^{2 + }}$$

$$Z{n^{2 + }} + Cu \to Zn + C{u^{2 + }}$$

## Questions 7 of 50

Question:In dry cell the reaction which takes place at the zinc anode is

$$Z{n^{2 + }} + 2{e^ - } \to Zn(s)$$

$$Zn(s) \to Z{n^{2 + }} + 2{e^ - }$$

$$M{n^{2 + }} + 2{e^ - } \to Mn(s)$$

$$Mn(s) \to M{n^ + } + {e^ - } + 1.5V$$

## Questions 8 of 50

Question:The chemical reaction taking place at the anode of a cell is

Ionisation

Reduction

Oxidation

Hydrolysis

## Questions 9 of 50

Question:Which of the following reactions occurs at the cathode during the charging of a lead storage battery

$$P{b^{2 + }} + 2{e^ - } \to Pb$$

$$P{b^{2 + }} + SO_4^{2 - } \to PbS{O_4}$$

$$Pb \to P{b^{2 + }} + 2{e^ - }$$

$$PbS{O_4} + 2{H_2}O \to 2Pb{O_2} + 4SO_4^{2 - } + 2{e^ - }$$

## Questions 10 of 50

Question:Which of the following statements are true for an fuel cells

They run till the reactants are active

They are free from pollution

They are more efficient

All of the above

## Questions 11 of 50

Question:For gold plating, the electrolyte used is

$$AuC{l_3}$$

$$HAuC{l_4}$$

$$k[Au{(CN)_2}]$$

None of these

## Questions 12 of 50

Question:The acid used in lead storage battery is

$${H_2}S{O_4}$$

$${H_3}P{O_4}$$

HCl

$$HN{O_3}$$

## Questions 13 of 50

Question:Conductivity (unit Siemen’s) is directly proportional to area of the vessel and the concentration of the solution in it and is inversely proportional to the length of the vessel then the unit of the constant of proportionality is

$$Sm\,\,mo{l^{ - 1}}$$

$$S{m^2}\,\,mo{l^{ - 1}}$$

$${S^{ - 2}}{m^2}\,\,mo{l^{}}$$

$${S^2}{m^2}\,\,mo{l^{ - 2}}$$

## Questions 14 of 50

Question:If one end of a piece of a metal is heated, the other end becomes hot after some time. This is due to

Energised electrons moving to the other part of the metal

Resistance of the metal

Mobility of atoms in the metal

Minor perturbation in the energy of atoms

## Questions 15 of 50

Question:Conductivity of a solution is directly proportional to

Dilution

Number of ions

Current density

Volume of the solution

## Questions 16 of 50

Question:The unit of molar conductivity is

$${\Omega ^{ - 1}}c{m^{ - 2}}mo{l^{ - 1}}$$

$${\Omega ^{}}c{m^{ - 2}}mo{l^{ - 1}}$$

$${\Omega ^{ - 1}}c{m^2}mo{l^{ - 1}}$$

$$\Omega \;c{m^2}mol$$

## Questions 17 of 50

Question:The highest electrical conductivity of the following aqueous solutions is of

0.1 M acetic acid

0.1 M chloroacetic acid

0.1 M fluoroacetic acid

0.1 M difluoroacetic acid

## Questions 18 of 50

Question:Given $$l/a = 0.5c{m^{ - 1}},\,R = 50ohm,\,N = 1.0$$. The equivalent conductance of the electrolytic cell is

$$10\,oh{m^{ - 1}}c{m^2}gm\,e{q^{ - 1}}$$

$$20\,oh{m^{ - 1}}c{m^2}gm\,e{q^{ - 1}}$$

$$300\,oh{m^{ - 1}}c{m^2}gme{q^{ - 1}}$$

$$100oh{m^{ - 1}}c{m^2}\,gme{q^{ - 1}}$$

## Questions 19 of 50

Question:The standard oxidation potential of zinc and silver in water at $$298\,\,K$$are: $$Zn\,\,(s)\,\, \to \,\,Z{n^{2 + }} + 2{e^ - }\,;\,E = 0.76\,V$$ $$Ag\,\,(s)\,\, \to \,A{g^{2 + }} + 2{e^ - }\,;\,E = - 0.80\,V$$. Which of the following reactions actually take place

$$Zn(s) + 2A{g^ + }(aq)\, \to \,Z{n^{ + + }}(aq) + 2Ag(s)$$

$$Z{n^{ + + }}(aq) + 2Ag(s)\, \to \,2A{g^ + }(aq) + Zn(s)$$

$$Zn(s) + Ag(s)\, \to \,Z{n^{ + + }}(aq) + A{g^ + }(aq)$$

$$Z{n^{ + + }}(aq) + A{g^ + }(aq)\, \to \,Zn(s) + Ag(s)$$

## Questions 20 of 50

Question:Beryllium is placed above magnesium in the second group. Beryllium dust, therefore when added to $$MgC{l_2}$$solution will

Have no effect

Precipitate $$Mg$$ metal

Precipitate $$MgO$$

Lead to dissolution of $$Be$$metal

## Questions 21 of 50

Question:$$EMF$$of cell $$Ni\,\,|\,\,N{i^{2 + }}\,(1.0\,M)\,\,||\,\,A{u^{3 + }}\,(1.0\,M)\,\,|\,\,Au$$ (Where $${E^o}$$ for $$N{i^{2 + }}\,\,|\,\,Ni$$ is $$- 0.25\,\,V;\,\,{E^o}$$ for $$A{u^{ + 3\,}}\,|\,\,Au$$ is $$1.50\,\,V)$$ is

+ 1.25 V

$$- \,1.75\,\,V$$

+ 1.75 V

+ 4.0 V

## Questions 22 of 50

Question:Oxidation and reduction take place in a cell, then its electromotive force will be

Positive

Negative

Zero

Stable

## Questions 23 of 50

Question:Reduction potential of four elements $$P,\,\,Q,\,\,R,\,\,S$$ is $$- \,2.90,\, + \,0.34,\, + \,1.20$$ and $$- \,0.76.$$ Reactivity decreases in the order

$$P > Q > R > S$$

$$Q > P > R > S$$

$$R > Q > S > P$$

$$P > S > Q > R$$

## Questions 24 of 50

Question:Which of the following metal can deposit copper from copper sulphate solution

Mercury

Iron

Gold

Platinum

## Questions 25 of 50

Question:The standard reduction potentials of 4 elements are given below. Which of the following will be the most suitable reducing agent I = – 3.04 V, II = – 1.90 V, III = 0 V, IV = 1.90 V

I

II

III

IV

## Questions 26 of 50

Question:Electrode potential data are given below : $$F{e^{3 + }}(aq) + {e^ - } \to F{e^{ - 1}}(aq);\,{E^o} = + 0.77V$$ $$A{l^{3 + }}(aq) + 3{e^ - } \to Al(s);\,{E^o} = - 1.66V$$ $$B{r_2}(aq) + 2{e^ - } \to 2B{r^ - }(aq);\,{E^o} = + 1.08\,V$$ Based on the data given above, reducing power of $$F{e^{2 + }},\,Al$$ and $$B{r^ - }$$ will increase in the order

$$B{r^ - } < F{e^{2 + }} < Al$$

$$F{e^{2 + }} < Al < B{r^ - }$$

$$Al < B{r^ - } < F{e^{2 + }}$$

$$Al < F{e^{2 + }} < B{r^ - }$$

## Questions 27 of 50

Question:Which of the following is displaced by $$Fe$$

$$Ag$$

$$Hg$$

$$Zn$$

$$Na$$

## Questions 28 of 50

Question:The standard electrode potential of the half cells are given below $$Z{n^{2 + }} + 2{e^ - } \to Zn;E = - 7.62\,\,V,$$$$F{e^{2 + }} + 2{e^ - } \to Fe;E = - 7.81\,\,V$$ The emf of the cell $$F{e^{2 + }} + Zn \to Z{n^{2 + }} + Fe$$ is

1.54 V

1.54 V

0.19 V

+ 0.19 V

## Questions 29 of 50

Question:Which of the following has highest electrode potential

$$Li$$

$$Cu$$

$$Au$$

$$Al$$

## Questions 30 of 50

Question:The cell reaction of a cell is $$M{g_{(s)}} + C{u^{2 + }}(aq) \to C{u_{(s)}} + M{g^{2 + }}(aq)$$ If the standard reduction potentials of $$Mg$$ and $$Cu$$ are $$- \,2.37$$ and $$+ \,0.34\,V$$ respectively. The emf of the cell is

2.03 V

2.03 V

+ 2.71 V

2.71 V

## Questions 31 of 50

Question:The strongest reducing agent of the alkali metal is

$$Li$$

$$Na$$

$$K$$

$$Cs$$

## Questions 32 of 50

Question:Which of the following is the most electropositive element

Carbon

Calcium

Chlorine

Potassium

## Questions 33 of 50

Question:$$Zn(s) + C{l_2}(1\;{\rm{atm)}} \to {\rm{Z}}{{\rm{n}}^{{\rm{2}} + }} + 2C{l^ - }$$. $${E^0}_{cell}$$ of the cell is 2.12 V. To increase E

$$[Z{n^{2 + }}]$$ should be increased

$$[Z{n^{2 + }}]$$ should be decreased

$$[C{l^ - }]$$should be decreased

$${P_{C{l_2}}}$$should be decreased

## Questions 34 of 50

Question:The $${E^0}_{{M^{3 + }}/{M^{2 + }}}$$values for $$Cr,\;Mn,\;Fe$$and $$Co$$are $$- 0.41,\; + 1.57,\; + 0.77$$and $$+ 1.97\;V$$ respectively. For which one of these metals the change in oxidation state from $$+ 2$$ to $$+ 3$$is easiest

$$Fe$$

Mn

Cr

Co

## Questions 35 of 50

Question:Which one of the following metals could not be obtained on electrolysis of aqueous solution of its salts

$$Ag$$

$$Mg$$

$$Cu$$

$$Cr$$

## Questions 36 of 50

Question:Which of the following aqueous solution will conduct an electric current quite well

Glycerol

$$HCl$$

Sugar

Pure water

## Questions 37 of 50

Question:When a solution of an electrolyte is heated the conductance of the solution

Increases because of the electrolyte conducts better

Decreases because of the increased heat

Decreases because of the dissociation of the electrolyte is suppressed

Increases because the electrolyte is dissociated more

## Questions 38 of 50

Question:The passage of current liberates $${H_2}$$ at cathode and $$C{l_2}$$ at anode. The solution is

Copper chloride in water

$$NaCl$$ in water

$${H_2}S{O_4}$$

Water

## Questions 39 of 50

Question:Which of the following metals will give $${H_2}$$ on reaction with NaOH

Mg

Ba

Ca

Sr

## Questions 40 of 50

Question:Which of the following is not a non electrolyte

Acetic acid

Glucose

Ethanol

Urea

## Questions 41 of 50

Question:In an electroplating experiment $$m\,\,g$$of silver is deposited, when 4 amperes of current flows for 2 minutes. The amount (in $$gms$$) of silver deposited by 6 amperes of current flowing for 40 seconds will be

$$4m$$

$$m/2$$

$$m/4$$

$$2m$$

## Questions 42 of 50

Question:On passing 3 ampere of electricity for 50 minutes, 1.8 gram metal deposits. The equivalent mass of metal is

20.5

25.8

19.3

30.7

## Questions 43 of 50

Question:What is the amount of chlorine evolved when 2 amperes of current is passed for 30 minutes in an aqueous solution of $$NaCl$$

66 g

1.32 g

33 g

99 g

## Questions 44 of 50

Question:On passing a current through $$KCl$$ solution, $$19.5\,g$$ of potassium is deposited. If the same quantity of electricity is passed through a solution of aluminium chloride, the amount of aluminium deposited is

4.5 g

9.0 g

13.5 g

27 g

None is correct

## Questions 45 of 50

Question:The electrolytic cells, one containing acidified ferrous chloride and another acidified ferric chloride are connected in series. The ratio of iron deposited at cathodes in the two cells when electricity is passed through the cells will be

3:01

2:01

1:01

3:02

## Questions 46 of 50

Question:When 96500 coulomb of electricity is passed through a copper sulphate solution, the amount of copper deposited will be

0.25 mol

0.50 mol

1.00 mol

2.00 mol

## Questions 47 of 50

Question:The number of coulombs required for the deposition of 107.870 g of silver is

96,500

48,250

1,93,000

10,000

## Questions 48 of 50

Question:When one of ampere current flows for $$1\,\sec$$through a conductor, this quantity of electricity is known as

Coulomb

E.M.F.

Ohm

## Questions 49 of 50

Question:4 g of copper was dissolved in concentrated nitric acid. The copper nitrate solution on strong heating gave 5 g of its oxide. The equivalent weight of copper is

23

32

12

20

## Questions 50 of 50

Question:The amount of silver deposited by passing 241.25 coulomb of current through silver nitrate solution is