Electrochemistry Test 5

Total Questions:50 Total Time: 75 Min

Remaining:

 

Questions 1 of 50

Question:For cell reaction, \(Zn + C{u^{2 + }} \to Z{n^{2 + }} + Cu,\) cell representation is cell cell

Answers Choices:

Zn | Zn2+||Cu2+|Cu

Cu | Cu2+ ||Zn2+| Zn

Cu | Zn2+ || Zn | Cu2+

Cu2+ | Zn || Zn2+ | Cu

Questions 2 of 50

Question:Which one is not called a anode reaction from the following

Answers Choices:

\(C{l^ - }\, \to \,\frac{1}{2}C{l_2} + {e^ - }\)

\(Cu\, \to \,C{u^{ + + }} + 2{e^ - }\)

\(H{g^ + }\, \to \,H{g^{ + + }} + {e^ - }\)

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

Questions 3 of 50

Question:In the reaction\(Cu(s) + 2A{g^ + }(aq) \to C{u^{2 + }}(aq) + 2Ag(s)\) The reduction half-cell reaction is

Answers Choices:

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

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

\(A{g^ + } + {e^ - } \to Ag\)

\(Ag - {e^ - } \to A{g^ + }\)

Questions 4 of 50

Question:Which of the following statements about galvanic cell is incorrect

Answers Choices:

Anode is positive

Oxidation occurs at the electrode with lower reduction potential

Cathode is positive

Reduction occurs at cathode

Questions 5 of 50

Question:If a strip of \(Cu\) metal is placed in a solution of ferrous sulphate

Answers Choices:

Copper will precipitate out

Iron will precipitate out

Copper will dissolve

No reaction will take place

Questions 6 of 50

Question:Which of the following is not used to construct salt bridge

Answers Choices:

\(C{H_3}COOK\)

\(KCl\)

\(N{H_4}N{O_3}\)

\(KN{O_3}\)

Questions 7 of 50

Question:The reference electrode is made by using

Answers Choices:

\(ZnC{l_2}\)

\(CuS{O_4}\)

\(HgC{l_2}\)

\(H{g_2}C{l_2}\)

Questions 8 of 50

Question:When electric current is supplied through an ionic hydride of fused state, then

Answers Choices:

Hydrogen is obtained at anode

Hydrogen is obtained at cathode

No change

Hydride ion moves towards cathode hydride ion present in solution

Questions 9 of 50

Question:Which one of the following statements is correct

Answers Choices:

The oxidation number of oxygen in \(K{O_2}\) is zero

The specific conductance of an electrolyte solution decreases with increase in dilution

\(S{n^{2 + }}\) oxidises \(F{e^{3 + }}\)

\(Zn/ZnS{O_4}\) is a reference electrode

Questions 10 of 50

Question:In infinite dilutions, the equivalent conductances of \(B{a^{2 + }}\) and \(C{l^ - }\) are 127 and 76 \(oh{m^{ - 1}}c{m^{ - 1}}\) \(eqv{t^{ - 1}}\). The equivalent conductivity of \(BaC{l_2}\)at indefinite dilution is

Answers Choices:

101.5

139.5

203.5

279.5

Questions 11 of 50

Question:The electrolytic conductance is a direct measure of

Answers Choices:

Resistance

Potential

Concentration

Dissociation

Questions 12 of 50

Question:Conductivity of a strong electrolyte

Answers Choices:

Increases on dilution

Does not change considerably on dilution

Decreases on dilution

Depends on density

Questions 13 of 50

Question:Which of the following statements is not applicable to electrolytic conductors

Answers Choices:

New products show up at the electrodes

Ions are responsible for carrying the current

Show a positive temperature coefficient for conductance

A single stream of electrons flows from cathode to anode

Questions 14 of 50

Question:The hydrogen electrode is dipped in a solution of \(pH = 3\) at \({25^o}C\). The potential of the cell would be (the value of \(2.303RT/F\) is 0.059 V)

Answers Choices:

0.177 V

0.177 V

0.087 V

0.059 V

Questions 15 of 50

Question:The standard electrode potentials of \(Z{n^{2 + }}/Zn\) and \(A{g^ + }/Ag\) are \( - \,0.763\,V\) and \( + \,0.799\,V\) respectively. The standard potential of the cell is

Answers Choices:

1.56 V

0.036 V

1.562 V

0.799 V

Questions 16 of 50

Question:The standard reduction potentials at \(298\,K\)for the following half reactions are given against each \(Z{n^{2 + }}(aq.) + 2e\)?\(Zn(s)\); – 0.762 \(C{r^{3 + }}(aq) + 3e\)?\(Cr(s)\); – 0.740 \(2{H^ + }(aq) + 2e\)?\({H_2}(g)\); 0.00 \(F{e^{3 + }}(aq) + e\)?\(F{e^{2 + }}(aq)\); 0.770 . Which is the strongest reducing agent

Answers Choices:

\(Zn(s)\)

\(Cr(s)\)

\({H_2}(g)\)

\(F{e^{2 + }}(aq)\)

Questions 17 of 50

Question:Which one of the following metals cannot evolve \({H_2}\)from acids or \({H_2}O\) or from its compounds

Answers Choices:

\(Hg\)

\(Al\)

\(Pb\)

\(Fe\)

Questions 18 of 50

Question:Which one of the following reaction is not possible

Answers Choices:

\(Fe + {H_2}S{O_4}\, \to \,\,FeS{O_4} + {H_2}\)

\(Cu + 2AgN{O_3}\, \to \,Cu\,{(N{O_3})_2} + 2Ag\)

\(2KBr + {I_2}\, \to \,\,2KI + B{r_2}\)

\(CuO + {H_2}\, \to \,\,Cu + {H_2}O\)

Questions 19 of 50

Question:When a rod of metal \(A\) is dipped in an aqueous solution of metal \(B\)(concentration of \({B^{2 + }}\)ion being 1M) at \({25^o}C\), the standard electrode potentials are \({A^{2 + }}/A\)=–0.76 volts, \({B^{2 + }}\)/B = + 0.34 volts

Answers Choices:

\(A\) will gradually dissolve

\(B\) will deposit on \(A\)

No reaction will occur

Water will decompose into \({H_2}\) and \({O_2}\)

Questions 20 of 50

Question:The standard reduction potential for \(F{e^{2 + }}/Fe\) and \(S{n^{2 + }}/Sn\) electrodes are \( - 0.44\) and \( - 0.14\) volt respectively. For the given cell reaction \(F{e^{2 + }} + Sn\, \to Fe + S{n^{2 + }}\), the standard EMF is

Answers Choices:

+ 0.30 V

0.58 V

+ 0.58 V

0.30V

Questions 21 of 50

Question:Electrode potential of \(Z{n^{2 + }}/Zn\) is \( - 0.76\,V\) and that of \(C{u^{2 + }}/Cu\) is \( + 0.34V\). The EMF of the cell constructed between these two electrodes is

Answers Choices:

1.10 V

0.42 V

1.1V

0.42 V

Questions 22 of 50

Question:EMF of a cell whose half cells are given below is \(M{g^{2 + }} + 2{e^ - } \to Mg(s);\,\,E = - 2.37\,V\) , \(C{u^{2 + }} + 2{e^ - } \to Cu(s);\,\,\,E = + 0.33\,V\)

Answers Choices:

2.03 V

1.36 V

2.7 V

2.03 V

Questions 23 of 50

Question:(i) Copper metal dissolves in 1M silver nitrate solution and crystals of silver metal get deposited. (ii) Silver metal does not react with 1 M zinc nitrate solution (iii) Zinc metal dissolves in 1M copper sulphate solution and copper metal gets deposited. Hence the order of decreasing strength of the three metals as reducing agents will be

Answers Choices:

\(Cu\, > \,Ag\, > \,Zn\)

\(Ag\, > \,Cu\, > \,Zn\)

\(Zn\, > \,Cu\, > \,Ag\)

\(Cu\, > \,Zn\, > \,Ag\)

Questions 24 of 50

Question:Standard electrode potentials of \(Zn\) and \(Fe\) are known to be (i) \( - 0.76\,V\) and (ii) \( - 0.44\,V\) respectively. How does it explain that galvanization prevents rusting of iron while zinc slowly dissolves away

Answers Choices:

Since (i) is less than (ii), zinc becomes the cathode and iron the anode

Since (i) is less than (ii), zinc becomes the anode and iron the cathode

Since (i) is more than (ii), zinc becomes the anode and iron the cathode

Since (i) is more than (ii), zinc becomes the cathode and iron the anode

Questions 25 of 50

Question:The e.m.f. of the cell in which the following reaction \(Zn(s) + N{i^{2 + }}(a = 1.0)\)? \(Z{n^{2 + }}(a = 10) + Ni(s)\) occurs, is found to be \(0.5105\,V\) at \(298K\). The standard e.m.f. of the cell is

Answers Choices:

0.54

0.4810 V

0.5696 V

0.5105 V

Questions 26 of 50

Question:For the redox reaction \(Zn(s) + C{u^{2 + }}(0.1M) \to Z{n^{2 + }}(1M) + Cu(s)\) taking place in a cell, \(E_{cell}^o\) is 1.10 volt. \({E_{cell}}\) for the cell will be \(\left( {2.303\frac{{RT}}{F} = 0.0591} \right)\)

Answers Choices:

2.14 volt

1.80 volt

1.07 volt

0.82 volt

Questions 27 of 50

Question:Which will increase the voltage of the cell \(S{n_{(s)}} + 2A{g^ + }_{(aq)} \to S{n^{2 + }}_{(aq)} + 2A{g_{(s)}}\)

Answers Choices:

Increase in the concentration of \(A{g^ + }\)ions

Increase in the concentration of \(S{n^{2 + }}\)ions

Increase in size of the silver rod

None of these

Questions 28 of 50

Question:The mass of the proton is 1840 times that of electron, its potential difference is V. The kinetic energy of proton is

Answers Choices:

1840 KeV

1 KeV

\(\frac{1}{{1840}}\) KeV

920 KeV

Questions 29 of 50

Question:In the experiment set up for the measurement of EMF of a half cell using a reference electrode and a salt bridge, when the salt bridge is removed, the voltage

Answers Choices:

Does not change

Decreases to half the value

Increase to maximum

Drops to zero

Questions 30 of 50

Question:Electrode potentials of five elements \(A,\,B,\,C,\,D\) and \(E\) are respectively – 1.36 , – 0.32, 0, – 1.26 and –0.42. The reactivity order of these elements are in the order of

Answers Choices:

A, D, E, B and C

C, B, E, D and A

B, D, E, A and C

C, A, E, D and B

Questions 31 of 50

Question:For the cell reaction, \(2C{e^{4 + }} + Co \to 2C{e^{3 + }} + C{o^{2 + }}\) \(E{^\circ _{cell}}\)is 1.89 V. If \(E{^\circ _{C{e^{4 + }}/C{e^{3 + }}}}\)

Answers Choices:

1.64 V

+ 1.64 V

2.08 V

+ 2.17 V

Questions 32 of 50

Question:If the \(\Delta G\) of a cell reaction \(AgCl + {e^ - } \to Ag + C{l^ - }\) is \( - 21.20\;KJ\); the standard e.m.f., of cell is

Answers Choices:

0.229 V

0.220 V

0.220 V

0.110 V

Questions 33 of 50

Question:For the feasibility of a redox reaction in a cell, the e.m.f. should be

Answers Choices:

Positive

Fixed

Zero

Negative

Questions 34 of 50

Question:Which of the following will not conduct electricity in aqueous solution

Answers Choices:

Copper sulphate

Sugar

Common salt

None of these

Questions 35 of 50

Question:A solution of sodium sulphate in water is electrolysed using inert electrodes. The products at the cathode and anode are respectively

Answers Choices:

\({H_2},\,\,\,{O_2}\)

\({O_2},\,\,{H_2}\)

\({O_2},\,\,Na\)

\({O_2},\,\,S{O_2}\)

Questions 36 of 50

Question:On electrolysing a solution of dilute \({H_2}S{O_4}\) between platinum electrodes, the gas evolved at the anode is

Answers Choices:

\(S{O_2}\)

\(I{F_5}\)

\({O_2}\)

\({H_2}\)

Questions 37 of 50

Question:Which of the following is non-electrolytes

Answers Choices:

\(NaCl\)

\(CaC{l_2}\)

\({C_{12}}{H_{22}}{O_{11}}\)

\(C{H_3}COOH\)

Questions 38 of 50

Question:When a molten ionic hydride is electrolysed

Answers Choices:

Hydrogen is liberated at the cathode

Hydrogen is liberated at the anode

There is no reaction

\({H^ - }\) ions produced migrate to the cathode

Questions 39 of 50

Question:A certain current liberated 0.504 gm of hydrogen in 2 hours. How many grams of copper can be liberated by the same current flowing for the same time in a copper sulphate solution

Answers Choices:

12.7 gm

15.9 gm

31.8 gm

63.5 gm

Questions 40 of 50

Question:What weight of copper will be deposited by passing 2 Faradays of electricity through a cupric salt (Atomic weight of Cu = 63.5)

Answers Choices:

2.0 gm

3.175 gm

63.5 gm

127.0 gm

Questions 41 of 50

Question:In electrolysis of a fused salt, the weight of the deposit on an electrode will not depend on

Answers Choices:

Temperature of the bath

Current intensity

Electrochemical equivalent of ions

Time for electrolysis

Questions 42 of 50

Question:Faraday's laws of electrolysis will fail when

Answers Choices:

Temperature is increased

Inert electrodes are used

A mixture of electrolytes is used

In none of these cases

Questions 43 of 50

Question:How much chlorine will be liberated on passing one ampere current for 30 minutes through NaCl solution

Answers Choices:

0.66 mole

0.33 mole

0.66 gm

0.33 gm

Questions 44 of 50

Question:The number of electrons involved in redox reactions when a Faraday of electricity is passed through an electrolyte in solution is

Answers Choices:

\(6 \times {10^{23}}\)

\(6 \times {10^{ - 23}}\)

96500

\(8 \times {10^{19}}\)

Questions 45 of 50

Question:Three faradays of electricity are passed through molten \(A{l_2}{O_3}\), aqueous solution of \(CuS{O_4}\) and molten \(NaCl\) taken in different electrolytic cells. The amount of \(Al,\,Cu\) and \(Na\) deposited at the cathodes will be in the ratio of

Answers Choices:

1 mole : 2 mole : 3 mole

3 mole : 2 mole : 1mole

1 mole : 1.5 mole : 3 mole

1.5 mole : 2 mole : 3 mole

Questions 46 of 50

Question:An electrolytic cell contains a solution of \(A{g_2}S{O_4}\) and have platinum electrodes. A current is passed until 1.6 gm of \({O_2}\) has been liberated at anode. The amount of silver deposited at cathode would be

Answers Choices:

107.88 gm

1.6 gm

0.8 gm

21.60 gm

Questions 47 of 50

Question:In order to separate oxygen from one mole of \({H_2}O\) the required quantity of coulomb would be

Answers Choices:

\(1.93 \times {10^5}\)

\(9.6 \times {10^4}\)

1.8

3.2

Questions 48 of 50

Question:A current of 0.25A is passed through \(CuS{O_4}\) solution placed in voltameter for 45 minutes. The amount of Cu deposited on cathode is (At weight of \(Cu = 63.6\))

Answers Choices:

0.20 g

0.22 g

0.25 g

0.30 g

Questions 49 of 50

Question:The number of coulombs required to reduce 12.3 g of nitrobenzene to aniline

Answers Choices:

115800 C

5790 C

28950 C

57900 C

Questions 50 of 50

Question:During the process of electrolytic refining of copper, some metals present as impurity settle as 'anode mud'. These are

Answers Choices:

Sn and Ag

Pb and Zn

Ag and Au

Fe and Ni