MDCAT CHEMISTRY-Electrochemistry (SMART INSTITUTE)

01-Magnesium metal is extracted by the electrolysis of its:

Concentrated aqueous solution of its chloride

Dilute aqueous solution of its chloride

Its fused chloride

Any solution

02-Iron can be prevented from rusting by:

Connecting iron to more electropositive metal, a case of cathodic protection

Connecting iron to more electropositive metal, a case of anodic protection

Connecting iron to less electropositive metal, a case of anodic protection

Connecting iron to less electropositive metal, a case of cathodic protection

03-Standard hydrogen electrode has an arbitrary fixed potential of

0 V

0.1 V

1.0 V

0.001 V

04-The correct order of equivalent conductance at infinite dilution among LiCl, NaCl and KCl is

LiCl > NaCl > KCl

NaCl > KCl > LiCl

KCl > NaCl > LiCl

LiCl > KCl > NaCl

05-Electrochemical series is useful in:

Prediction of the feasibility of a chemical reaction

Calculation of voltage

Comparison of the relative tendencies of the metals and non-metals to get oxidized or reduced

All of above

06-Normal Aluminum electrode coupled with normal hydrogen electrode gives an element of 1.66 volts and deflection of needle towards Hydrogen. The standard electrode potential of Aluminum is:

-1.66 V

-0.83 V

+1.66 V

+0.83 V

07-If the sum of E^o values of the two half-cells is negative, then

The reaction will be feasible

The reaction may or may not be feasible

The reaction will not be feasible

No prediction can be made

08-WOF cell can convert electrical energy directly into chemical series.

Silver battery

Lead storage battery

Daniel cell

Down's cell

09-In a Galvanic cell, the electrode occupying a lower position in the electrochemical series.

A) will act as cathode

B) reduction will take place on it

C) oxidation will take place on it

Both a and b

10-WOF statement is true about Galvanic cell:

Anode is positively charged

Carhode is negatively charged

Reduction occurs at anode

Reduction occurs at cathode

11-Greater the value of the standard reduction potential of the given specie:

Greater is its tendency to accept electrons to undergo reduction

Greater is its tendency to accept electron to undergo oxidation

Greater is its tendency to lose electrons to undergo reduction

Greater is its tendency to lose electrons to undergo oxidation

12-Coinage metals have least reactivity because they have

Positive oxidation potentials

Zero oxidation potentials

Positive reduction potentials

Zero reduction potentials

13-WOF is a secondary cell:

Dry cell

Ni-Cd cell

Mercury cell

Alkali cell

14-Four metals A,B,C and D are having standard electrode potentials as -3.05, -1.66, -0.4 and 0.8 V respectively. Which one will be the best reducing agent?

15-The oxidation potential of Mg and Al are +2.37 V and 1.66V, respectively. The Mg in chemical reaction:

Will be replaced by Al

Would not be able to replace Al

Will replace Al

None of above

16-Which can replace Hydrogen from dilute acids?

NONE OF THESE

17-The oxidation state of carbon-atom in glucose is

-4

None of these

18-The cell in which electrical energy is converted into chemical energy is

Galvanic cell

Electrolytic cell

Voltaic cell

All of these

19-The ability of elements to act as reducing agent ........ Down to electrochemical series.

Increases

Remains constant

Decreases

Depends upon the reaction conditions

20-If a strip of Cu-metal is placed in a solution of FeSO4 then

Cu will be deposited

Cu Fe both dissolve

Fe is precipitated

NO reaction occur

21. "Al" metal is extracted from its ....... During electrolysis.

Chloride

Cryolite

Oxides

All of these

22-Halogens are placed at lower level of electrochemical series, this indicates that

Halogens are good reducing agents

Halogens are good oxidizing agents but bad reducing agents

Halogens are good oxidizing agents as well as good reducing agents

All of the above statements are correct

23-The electrolysis product of molten NaCl at electrodes

Na and Cl2

Na and NaOH

H2 and Cl2

H2, Cl2 and NaOH

24. SHE acts as anode when connected with Cu electrode but cathode with Zn electrode because

Zn has less reduction potential than hydrogen and Cu more

Zn has high oxidizing potential than hydrogen and Cu more

Zn is above in electrochemical series than hydrogen and Cu below

All the above are possible reasons.

25-When an element is in contact with 1M aqueous solution of its own ions, at 298K then potential is called?

A) standard reduction potential

B) reduction potential

C) standard electrode potential

Both a and c

26-Gold and Silver are least reactive due to

Positive oxidation state

Zero oxidation state

Positive reduction potential

Having large negative electrode potential

27-During the electrolysis of aqueous KNO3, H2 is produced at cathode instead potassium due to:

Reduction potential of "K" is greater than hydrogen

Hydrogen is more reactive than potassium

Reduction potential of potassium is less than hydrogen

All of above are possible reasons

28-WOF statement is correct?

Zn can replace Cu+2 in CuSO4

Cu can replace H+ in H2SO4

Cu can replace Zn+2 in ZnSO4

NONE OF THESE

29-In a reaction Zn + HNO3 → Zn(NO3)2 + NO + H2O

Zn is reduced

N is oxidized

N is reduced

H is reduced

30-The cell will function best if its calculated emf is

Small +ve

Large +ve

Small -ve

Large -ve

32-NaCl is strong electrolyte because

It dissolves rapidly in water

It completely dissociates into ions at all concentrations

It conducts electricity

It dissociates into its constituents

33-If a salt bridge is removed from two half-cells

Reaction will stop

Emf drop to zero

Emf is decreased

Electrodes will reversed

34-Fuel cells usually operate at

Low temperature

Moderate temperature

High temperature

At all temperature

35-The reduction potential of Cu = +0.34V and Zn = -0.76V. When these two are coupled, the emf of cell is

-0.42V

+0.42V

-1.10V

+1.10V

36. 8H+ MnO4- → Mn+2 + 4H2O, which one is correct about given equation

5e- in R.H.S

3e- in R.H.S

5e- in L.H.S

3e- in L.H.S

37.WOF reactions occur at cathode

Cu+2 + 2e- → Cu

Hg + 1/2 O2 → HgO

Cu + 2e- → Cu+2

Mg + 1/2 O2 → MgO

38-Which is correct statement for the element present at the top of electrochemical series

It has greater tendency to get oxidized

It can easily replace H2 from dilute acid

It has large positive reduction potential value

It can reduce the metal lower in electrochemical series

39-The two half-cells of the galvanic cells are connected with each other through a salt bridge which

Carries the electrons from one half cell to the other

Carries ions from one half cell to the other

Indicates the value of the e.m.f of cell

Carries out the electrolysis

40. Al / Al+3 || Zn+2 / Zn galvanic cell, the negative terminal is:

KCl

42-WOF cell can convert electrical energy directly into chemical energy:

Silver battery

Lead storage battery

Danie's cell

Down's cell / Electrolytic cell

44-In Zn/Zn+2 (1M) // Cu+2 (1M) / Cu Galvanic cell, which is incorrect statement

Zn is negatively charged

Zn will be oxidized

Cu is negatively charged

Cu+2 will be reduced

45-The value of reduction potential of elements is dependent upon:

Change in T

Change in concentration

Change in pressure

All of these

46-Cell potential depends upon

Temperature

Nature of electrolyte

Concentration of ions

All of these

47-Which change in oxidation state takes place in nitrogen?

Cu + HNO₃ → Cu(NO₃) + NO₂ + H₂O

+5 to -2

+5 to 0

+5 to +4

0 to -4

48-The element on the reactant side which has been reduced is

HI + H₂SO₄ → I₂ + SO₂ + H₂O

49-WOF metal will liberate hydrogen gas when react with steam:

50-A redox reaction is

MnO₂ + 4H+ → Mn⁺²_(aq) +2H₂O

2e are added on L.H.S

2e are added on R.H.S

4e are added on L.H.S

51. Li has least reduction potential in electrochemical series. Which element has highest E⁰ red

52-The value of oxidation potential would be positive if it is

A) below SHE

B) equal to SHE

C) above SHE

Both A and B

53-The standard reduction potential values of three metallic cations X, Y and Z are 0.52, -3.03 and -1.18 respectively. The order of reducing power of corresponding metal is:

Y>Z>X

Z>Y>X

X>Y>Z

Z>X>Y

54. E^o red values of metals are W =-3.06 V, X= +2.07 V, Y = -1.85V, Z = +1.14 indicate the least reactive metal.

55-In electrochemical series, metal will be easily oxidized if

E red = 0.521 V

E red = -1.66 V

E red = 1.08 V

E red = -0.76 V

56-An element having E^o red = -2.66 V. It is/will be:

Easily oxidized

Oxidizing agent

Easily reduced

Easily oxidize other metal

57-If E^o cell is positive, then reaction will be

Spontaneous/feasible

Endothermic

Non-spontaneous

Not feasible

58. Two half-cell reactions are

2H⁺ / H₂ E^o red = 0.00 V

Ag⁺¹ / Ag E^o red = +0.80

E^o_cell of cell is:

0.80 V

0.00 V

-0.80 V

-1.66 V

59-Zinc rod acts as anode in Daniel cell but acts as cathode when coupled with Al electrode, this is because the E^o red of:

Zn>Al

Zn=Al

Zn=0

60-Standard Hydrogen electrode has an arbitrary fixed potential of:

0 V

0.1 V

1.0 V

0.001 V

MDCAT CHEMISTRY-Electrochemistry (SMART INSTITUTE)

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