CHEMISTRY
1. ELECTROCHEMISTRY
Electrolysis
CONCEPTUAL BULLETS
Electrolytic conductors
1.
In which of the following, HCl conducts electricity to large extent ?
1) Liquid HCl
2) HCl aq. solution
3) HCl solution in benzene
4) Gaseous HCl
2.
Solid NaCl is a bad conductor of electricity
because
1) solid NaCl is a covalent compound
2) solid NaCl has no free ions
3) solid NaCl has no free electrons
4) solid NaCl has migration of ions
3.
The reason for increase in electrical conduction
of electrolyte with increase in temperature is
A) increase in the number of ions
B) increase in the speed of ions
C) increase in the degree of dissociation of
electrolyte
1) A, B only
2) B, C only
3) A, C only
4) A, B, C
Arrhenious theory
4.
Which of the following is 100% ionised at any
dilution ?
2) HCN
1) CH3COOH
3) NaCl
4) NH4OH
5.
The degree of dissociation of an electrolyte in
aqueous solution depends on
A) Temperature
B) Concentration of the electrolyte
C) Nature of the electrolyte
1) Only A
2) Only A, B
3) Only B, C
4) A, B, C
6.
104
What happens at infinite dilution in a given
solution ?
1) The degree of dissociation is unity for weak
electrolytes
2) The electrolyte is 100% ionised
3) All inter ionic attractions disappear
4) All the three
7.
The products of electrolysis of aqueous NaCl
solution are
1) Na at cathode and Cl2 at anode
2) H2 at cathode and Cl2 at anode
3) H2 at cathode and O2 at anode
4) Na at cathode and O2 at anode
8.
A dilute aqueous solution of Na2SO4 is electrolysed using platinum electrodes. The products
at the anode and cathode are
1) O2, H2
3) O2, Na
9.
2) SO2, Na
4) S2 O82 , H2
The products formed when an aqueous solution of NaBr is electrolysed in a cell having inert
electrodes are
2) Na and O2
1) Na and Br2
3) H2, Br2 and NaOH 4) H2 and O2
10. The reactions taking place at anode and cathode
are
1) Oxidation and Reduction
2) Reduction and Oxidation
3) Oxidation and Hydrolysis
4) Reduction and Hydrolysis
11. After the electrolysis of aqueous solution of
NaCl using Pt electrodes, the pH of the solution
1) increases
2) decreases
3) remains constant 4) becomes zero
Faradays laws
12. According to 2nd law of Faraday’s electrolysis
the correct one is
wt. of H2 liberated
eq. wt. of H2
i) wt. of Cl liberated = eq. wt. of Cl
2
2
ii)
iv)
m Ag
m Cu
m H2
E Ag
E H2
E Cu
m Ag ECu
iii) m E
Cu
Ag
m Cu ECu
The correct combination is
1) only ii, iv
2) only i
3) only i, ii , iv
4) only ii, iii
NEET Master Capsule for Sri Chaitanya Students
CHEMISTRY
Electrolytic conductance
13. Effect of dilution on conduction is as follows
1) Specific conductance increases, molar
conductance decreases
2) Specific conductance decreases, molar
conductance increases
3) Both increase with dilution
4) Both decrease with dilution
19. The cell for which the cell reaction is
H2 + Cu2+ → 2H+ + Cu is represented as
1) Cu Cu2+ H+ H2
2) H2(g) H+
3) Pt, H2(1 atm), H+
1) Oxidation potential
2) Reduction potential
3) Redox potential
4) Hydration potential
3) NaCl > KCl > LiCl 4) LiCl > KCl > NaCl
1) KCl
2) BaCl2
21. For spontaneity of a cell, which is correct ?
1)
3)
%G 0, %E 0
%G Ve, %E 0
2)
4)
%G Ve, %E 0
%G Ve
Electrode potentials and EMF
22. Standard reduction electrode potential of three
metals A, B and C are respectively + 0.05 V,
– 3.0 and – 1.2 V. The reducing powers of
1) B > C > A
2) A > B > C
3) C > B > A
4) A > C > B
23. At 298 K the standard reduction potentials for
the following half reactions are given as
Zn2+(aq) + 2e- → Zn(s) ; -0.762 V
Cr3+(aq) + 3e- → Cr(s) ; -0.740 V
Meq
2H+(aq) + 2e- → H2(g); -0.00 V
3) H2SO4
4) CH3COOH
Cu2+ Cu
20. Stronger the oxidising agent greater is the
1) LiCl > NaCl > KCl 2) KCl > NaCl > LiCl
16. A graph is drawn between the M eq values and
concentrations of an electrolyte. Which of the
following electrolyte will correspond to the
graph given ?
Cu2+ Cu
4) Pt, H2 H+(aq) (1atm)
14. The correct order of equivalent conductance at
infinite dilution of LiCl, NaCl and KCl is
15. The value of molar conductivity of HCl is
greater than that of NaCl at a particular
temperature because
1) Molecular mass of HCl is greater than that
of NaCl
2) Mobility of H+ ions is more than that of Na+
ions
3) HCl is strongly acidic
4) Ionisation of HCl is larger than that of NaCl
Cu2+ Cu
Fe3+ (aq) + e- → Fe2+(aq) ; + 0.770 V
The strongest reducing agent is
Conc.
17. For which case ' M ' values v/s
straight line
c shows a
1) KCl
2) HCOOH
3) CH3NH2
4) CH3COOH
2) H2(g)
1) Zn (s)
4) Fe2+(aq)
3) Cr(s)
24. The standard reduction potentials of Zn and Ag
in water at 298 K are,
Galvanic cells
18. The function of a salt bridge is
1) to provide a link between two half cells
2) to allow ions to go from one cell to another
3) to keep the emf of the cell positive
4) to maintain electrical neutrality of the
solution in two half cells
NEET Master Capsule for Sri Chaitanya Students
Zn2+ + 2e– → Zn ; E0 = – 0.76V and
Ag+ + e– → Ag ; E0 = + 0.80V
Which of the following reactions take place?
2
1) Zn
aq
3) Zn
4) Zn s
aq
m Zn s
Ag s m Zn2
2) Zn s
2
Ag
aq
aq
Ag
aq
aq
Zn s
aq
2Ag s m 2 Ag
2 Ag
Ag s
m Zn
2
aq
2Ag s
105
CHEMISTRY
25. The standard electrode potentials of four
elements A, B, C and D are – 2.65, – 1.66,
– 0.80 and + 0.86 V. The highest chemical
activity will be exhibited by
1) A
2) B
3) C
4) D
BULL’S EYE EXERCISE
Electrolytic conductance
1.
The specifce conductance of a 0.01 M solution
of KCl is 0.0014ohm -1 cm -1 at 25 0 C. Its
equivalent conductance is
1) 14
2) 140
2) 1.4
4) 0.14
2.
The equivalent conductivity of 0.1N CH3COOH
at 250C is 80 and at infinite dilution 400 ohm-1.
The degree of dissociation of CH3COOH is
1) 1
2) 0.2
2) 0.1
4) 0.5
3.
The electric conduction of a salt solution in water
depends on the
1) shape of molecules 2) size of its molecules
3) size of solvent molecules
4) extent of its ionisation
4.
Correct statements among the following :
i) Unit of specific conductivity is ohm–1cm–1
ii) Specific conductivity of strong electrolytes
decreases on dilution.
iii) The amount of an ion discharged during
electrolysis does not depend upon resistance
iv) The unit of electrochemical equivalence is
g/coulomb.
1) All are correct
2) All are wrong
3) Only i, ii and iv are correct
4) Only ii, iii and iv are correct
5.
If the equivalent conductance of 1M benzoic
acid is 12.8 ohm –1 cm 2 eq –1 and if the
conductance of benzoate ion and H+ ions are
42 and 288.42 ohm–1cm2 eq–1 respectively, its
degree of dissociation is:
1) 39%
2) 3.9%
3) 0.35% 4) 0.039%
6.
Equivalent conductances of NaCl, HCl and
CH 3 COONa at infinite dilution are 126.45,
426.16 and 91ohm–1cm2 eq–1 respectively. The
equivalent conductance of CH3COOH at infinite
dilution would be:
1) 101.38 ohm–1cm2 eq–1
2) 253.62 ohm–1cm2 eq–1
3) 390.71 ohm–1cm2 eq–1
4) 678.90 ohm–1cm2 eq–1
Nernst equation
26. The potential of single electrode depends upon
1) the nature of the electrode
2) temperature
3) concentration of the ion with respect to which
it is reversible
4) all the above
27. Zn
(s)
+ Cl2(1atm) → Zn2+ + 2Cl–
The E0 of the cell is 2.12 V. To increase E
1) Zn2+ concentration should be increased
2) Zn2+ concentration should be decreased
3) Cl– concentration should be increased
4) partial pressure of Cl2 should be decreased.
28. For a spontaneous reaction the % G , equilibrium
constant (K) and E0cell will be respectively
1) –ve , >1, +ve
2) –ve, >1, –ve
3) –ve, <1, –ve
4) –ve, >1, –ve
Batteries & Corrosion
29. When lead storage battery is discharged
1) SO2 is evolved
2) Lead sulphate is consumed
3) Lead is formed
4) H2SO4 is consumed
30. The reaction occuring at cathode during the
charging of lead storage batter is represented as
Pb2+ + 2e– 2) Pb2+ + 2e–
Pb
1) Pb
2+
2PbSO4
3) Pb + SO4
4) PbSO4+ 2H2O
PbO2 + 4H+ +SO42–+ 2e–
m
m
m
m
31. Galvanization process includes plating iron with
1) zinc
2) tin
3) copper
4) aluminium
32. The corrosion of iron object is favoured by
1) Presence of H+ ion
2) Presence of moisture in air
3) Presence of impurities in iron object
4) All of the above
106
NEET Master Capsule for Sri Chaitanya Students
CHEMISTRY
7.
The specific conductivity of N/10 KCl solution
at 200C is 0.0212 ohm–1cm–1 and the resitance
of the cell containing this solution at 200C is 55
ohm. The cell constant is:
2) 1.166 cm–1
1) 4.616 cm–1
3) 2.713 cm–1
4) 3.324 cm–1
14. Copper sulphate solution is electrolysed
between two platinum electrodes. A current is
passed until 1.6g of oxygen is liberated at
anode. The amount of copper deposited at the
cathode during the same period is
1) 6.36g 2) 63.6g 3) 12.7 g 4) 3.2 g
8.
The resistance of 1 N solution of CH3COOH is
250 ohm; when measured in a cell of cell
constant 1.15 cm–1. The equivalent conductance
will be:
1) 4.6 ohm–1cm 2 eq–1 2) 9.20 ohm–1cm 2 eq–1
3) 18.4 ohm –1cm 2 eq–1 4) 0.023 ohm –1cm2 eq–1
15. A solution of sodium sulphate in water is
electrolysed using platinum electrodes. The
products at cathode and anode are respectivley.
1) H2, O2 2) O2, H2 3) O2, Na 4) O2, SO2
9.
If the molar conductance values of Ca 2+ and
Cl – at infinite dilution are respectively
118.88 s 10 –4 m 2mho mol–1 and
77.33 s 10–4 m2mho mol–1 then that of CaCl2 is
: (in m2mho mol–1)
2) 154.66 s 10 –4
1) 118.88 s 10–4
3) 273.54 s 10–4
4) 196.21 s 10 –4
10. The molar conductivities of KCl, NaCl and
KNO 3 are 152, 128 and 111 S cm 2 mol -1
respectively. What is the molar conductivity of
NaNO3 ?
2) 87 S cm2 mol–1
1) 101 S cm2 mol–1
3) - 101 S cm2 mol–1 4) - 391 S cm2 mol–1
11. The unit of equivalent conductances is:
1) ohm cm
16. In electroplating, the article to be elelctroplated
serves as:
1) cathode
2) electrolyte
3) anode
4) conductor
17. A certain current liberated 0.504 g of hydrogen
in 2 hours. How many grams of copper can be
liberated by the same current flowing for the
same time in CuSO4 solution ?
1) 12.7 g 2) 15.9 g 3) 31.8 g 4) 63. 5 g
18. A chemist wants to produce Cl2(g) from molten
NaCl. How many grams could be produced if
he uses a steady current of 2 ampere for 2.5
minutes?
1) 3.55 g 2) 1.775 g 3) 0.110 g 4) 0.1775 g
19. In the electrolysis of CuCl2 solution, the mass
of cathode increased by 6.4 g. What occurred
at copper anode ?
1)
2)
3)
4)
2) ohm –1cm2 g equiv–1
3) ohm –1cm2 g equiv
4) ohm–2 cm–2 g equiv
Electrolysis & Faradays laws
12. On passing one faraday of electricity through a
dilute solution of an acid, the volume of
hydrogen obtained at NTP is :
1) 22400mL
2) 1120mL
3) 2240mL
4) 11200mL
13. w-g of copper is deposited in a copper
voltameter when an elecric current of 2 ampere
is passed for 2 hours. If 1 amp of electric current
is passed for 4 hours in the same voltameter,
copper deposited will be:
1) w
2) w/2
3) w/4
4) 2w
0.224 litre of Cl2 was liberated
1.12 litre of oxygen was liberated
0.05 mole Cu2+ passed into the solution
0.1 mole Cu2+ passed into the solution
20. Three mole of electrons are passed through three
solutions in succession containing AgNO 3 ,
CuSO 4 and AuCl 3 respectively. The ratio of
amounts of cations reduced at cathode will be:
1) 1 : 2 : 3
2) 2 : 1 : 3
3) 3 : 2 : 1
4) 6 : 3 : 2
21. In the electrolysis of an aqueous solution of
NaOH, 2.8 litre of oxygen gas at NTP was
liberated at anode. How much of hydrogen gas
was liberated at cathode ?
1) 2.8 ltr 2) 5.6 ltr 3) 11.2 ltr 4) 22.4 ltr
NEET Master Capsule for Sri Chaitanya Students
107
CHEMISTRY
22. An electric current of 1 amp is passed through
acidulated water for 160 minutes and 50
seconds. What is the volume of the hydrogen
librerated at the anode (as reduced to NTP) ?
1) 1.12 litre
2) 2.24 litre
3) 11.2 litre
4) 22.4 litre
Galvanic cells & Nernst equation
23. The standard oxidation potentials, E0, for the
half reactions are as,
Zn
Zn2+ +2e– ; E0 = +0.76 volt
Fe Fe2+ + 2e– ; E0 = +0.4 volt
The emf of the cell, Fe2+ + Zn
Zn2+ + Fe is
1) +0.35 volt
2) - 0.35 volt
3) +1.17 volt
4) - 1.17 volt
m
m
m
24. The standard reduction potentials at 250C for
the following half reactions are given against
each;
Zn 2 (aq.) 2e U Zn(s); 0.762 V
Cr (aq.) 3e U Cr(s); 0.740 V
2H
2e U H 2 g ; 0.00 V
Fe3
e U Fe 2 ; 0.77 V
Which is the strongest reducing agent ?
1) Zn
2) Cr
3) H2(g) 4) Fe2+(aq.)
25. The standard electrode potentials for the
reactions,
m Ag(s)
(aq.)+2e m Sn(s)
–
at 250C are 0.80 volt and - 0.14 volt respectively.
The emf of the cell,
2
Sn Sn 1M Ag 1M Ag is
1) 0.66 volt
2) 0.80 volt
3) 1.08 volt
4) 0.94 volt
3) - 0.591 volt
4) 0.059 volt
28. The position of some metals in the electrochemical series in decreasing electropositive
character is given as Mg > Al > Zn > Cu > Ag.
What will happen if a copper spoon is used to
stir a solution of aluminium nitrate ?
1) The spoon will get coated with aluminium
2) An alloy of aluminium and copper is formed
3) The solution becomes blue
4) There is no reaction
29. Out of Cu, Ag, Fe and Zn, the metal which can
displace all others from their salt solution is:
1) Ag
2) Cu
3) Fe
4) Zn
1) Zn Cu 2
2) Zn 2Ag
3) H 2
Cu 2
4) H 2
Ni 2
m Cu Zn
m 2Ag Zn
m 2H Cu
m 2H Ni
2
2
m
1) Increase in the size of silver rod
2) Increase in the concentration of Sn2+ ions
3) Increase in the concentration of Ag+ ions
4) None of the above
26. If the solution of the CuSO4 in which copper
rod is immersed is diluted to 10 times, the
electrode potential:
1) increases by 0.030 volt
2) decreases by 0.030 volt
3) increases by 0.059 volt
4) decreases by 0.0059 volt
108
2) 0 volt
31. Which one of the following will increase the
voltage of the cell ?
Sn +2Ag+
Sn2+ + 2Ag
Ag+(aq.)+e–
Sn2+
1) 0.21 volt
30. The oxidation potentials of Zn, Cu, Ag, H2 and
Ni are 0.76, - 0.34, - 0.80, 0 and 0.25 volt
respectively. Which of the following reactions
will provide maximum voltage?
3
27. The potential of a hydrogen electrode at pH =
10 is
32. The standard electrode potentials of Zn, Ag and
Cu are - 0.76, 0.80 and 0.34 volt respectively;
then;
1) Ag can oxidise Zn and Cu
2) Ag can reduce Zn2+ and Cu2+
3) Zn can reduce Ag+ and Cu2+
4) Cu can oxidise Zn and Ag
NEET Master Capsule for Sri Chaitanya Students
CHEMISTRY
33. In the electrochemical reaction,
m
3+
2+
2) Both conductance and molar conductance
decrease on increasing concentration
3) Conductance increase but molar conductance decrease on increasing concentration
4) Conductance dectreases but molar conductance increases on intreasing concentration
2+
2Fe + Zn Zn + 2Fe
increasing the concentration of Fe2+
1) increases the cell emf
2) increases the current flow
3) decreases the cell emf
4) alters the pH of the solution
3.
Which of the following statement concerning
concentration dependence of molar conductivity for a strong and a weak electrolyte is true?
1) Molar conductivity increases linearly on
increasing concentration for both types of
electrolytes
2) Molar conductivity decreases linearly on
increasing concentration for both types of
electrolytes
3) Molar conductivity decreases linearly on
dilution for strong electrolyte but is is
constant for weak electrolyte
4) On dilution, molar conductivity increases
linearly for strong electrolyte but for weak
electrolyte, the increase is gradual in higher
concentration range but very rapid in lower
concentration range
4.
Which of the following is not an essential
requirement for Kohlrausch’s law of independent migration of ions to hold true ?
1) The soluton must be infinitely dilute
2) Electrolyte must be strong
3) Electrolyte must be completely ionized
4) There should be no inter-ionic interaction
5.
Given the following molar conductivity at
infinite dilution and 250C.
HC1: - d 426.2 Scm 2 mol 1
34. In the cell reaction,
Cu(s) + 2Ag+(aq.) (Cu2+(aq.) + 2Ag(s.)
m
E 0cell 0.46V. By doubling the
concentration of Cu2 ,E 0cell is:
1) doubled
2) halved
3) increased but less than double
4) decreased by a small fraction
35. Given E 0Cr3 / Cr 0.72V, E 0Fe2
/ Fe
0.42V .
The potential for the cell
Cr Cr 3 0.1M Fe 2
0.01M Fe is
1) - 0.26V
3) 0.339 V
2) 0.26 V
4) -0.339 V
36. Efficiency of the following cell is 84%.
A(s) B (aq.) U A (aq.) B(s); %H 285kJ
Then the standard electrode potential of the cell
will be:
1) 1.20 V 2) 2.40 V 3) 1.10 V 4) 1.24 V
2
2
CHALLENGER’S EXERCISE
Electrolytic conductance
1.
The specific conductance of saturated solution
of AgCl is found to be
1.86 s 10 –6 ohm –1 cm –1 and that of water is
1 s 10–8 ohm–1cm–1 . The solubility of AgCl is
........ Given,
-0AgCl 137.2ohm 1cm2 eq1
1) 1.7 s 10–3 M
3) 1.3 s 10–4 M
2.
2) 1.3 s 10–5 M
4) 1.3 s 10–6 M
Which of the followming statement concerning
conductance and molar conductance is true?
1) Both conductance and molar conductance
increase on increasing concentration
NEET Master Capsule for Sri Chaitanya Students
m
d
KCl : - m
271.5 Scm2 mol1
CH3COOK : - dM 114.42S cm 2 mol 1
The molar conductance at infinite dilution and
250C for acetic acid solution is
1) 583.28 cm 2mol–1
2) 269.12 S cm2mol–1
3) 289.63 S cm2mol–1
4) 172.94 S cm2mol–1
109
CHEMISTRY
6.
7.
An aqueous solution of a weak acid (HA) has a
molar conductance of 19 S cm2mol–1 and it is
only 1% ionized in given condition. The limiting
value of molar conductance of above acid under
similar experimental condition is
1) 1900 S cm2mol–1 2) 950 S cm2mol–1
3) 475 S cm2mol–1
4) Infinite
For a strong electrolyte, dilution increases the
molar conductivity because
1) It increases the extent of ionization of
electrolyte
2) It increases the extent of ionization of water
3) It increases the inter- ionic interaction
4) It weaken the inter-ionic interaction
8.
The equivalent conductivity of 0.1N CH3COOH
at 25oC is 80 and at infinite dilution 400 ohm-1.
The degree of dissociation of CH3COOH is
1) 0.2
2) 0.1
3) 0.5
4) 1
9.
At 25 oC the molar conductances at infinite
dilution for the strong electrolytes NaOH, NaCl
and BaCl2 are 248 × 10–4, 126 × 10–4 and 280 ×
10–4 Sm2 mol-1 respectively. Molar conductivity
of Ba(OH)2 at infinite dilution is in Sm2 mol–1
1) 524 × 10–4
2) 402 ×10–4
3) 262 ×10–4
4) 52.4 ×10–4
10. Equivalent conductivity of BaCl2, KCl and KOH
is x,y,z mho cm 2 mole −1 respectively.
Equivalent conductance of Ba(OH)2 is
1) x 2z 2y
2) x z y
3)
x 2z 2y
2
4) 2(x 2z 2y)
Electrolysis & Faradays laws
11. 4.5 g of aluminium (At. mass=27 amu) is
deposited at cathode from Al 3+ solution by a
cerrain quantity of electric charge. The volume
of hydrogen produced at STP from H+ ions in
solution by the same quantity of electric charge
will be
110
1) 44.8 L
2) 22.4 L
3) 11.2 L
4) 5.6 L
12. Cost of electricity for the production of x L H2
at NTP at cathode is Rs. x; then cost of
production of x L O2 at NTP at anode will be;
(assume 1 mole of electrons as one unit of
electricity)
1) 2x
2) 4x
3) 16x
4) 32x
13. What current is to be passed for 0.25 sec for
deposition of certain weight of metal which is
equal to its electrochemical equivalent ?
1) 4 A
2) 100 A 3) 200 A 4) 2 A
14. One litre of 1 M CuSO4 solution is electrolysed.
After passing 2F charge, the molarity of CuSO4
will be
1) M/2
2) M/4
3) M
4) zero
15. The time required to coat a metal surface of 80
cm2 with 5 s 10–3 cm thick layer of silver(density
1.05g/cm 3 ) by passing a current of 3 amp
through silver nitrate solution is
1) 115 sec 2) 125 sec 3) 135 sec 4) 145 sec
16. The same quantity of electricity is passed
through 0.1 M H 2 SO 4 and 0.1M HCl. The
amounts of H2 obtained at the cathodes are in
the ratio
1) 1 : 1
2) 2 : 1
3) 1 : 2
4) 3 : 1
17. Acidified water was electrolysed using copper
electrodes. A steady current of 1.17 ampere was
passed for 25 min and 15s. The copper anode
lost 0.583g. Calculate the oxidation state of the
copper ion that was formed
1) + 1
2) + 2
3) –2
4) + 3
18. An electric current of 0.2F is passed through
2 lit of 0.25M CuSO 4 solution using ‘pt’
electrodes. After electrolysis the molarity of the
solution is (assume that there is no change in
the volume of solution)
1) 0.2M 2) 0.15M 3) 0.1M 4) 0.24M
19. The cost of electricity required to deposit 1g of
Mg is Rs.5. How much would it cost to deposit
10g of Al ?
1) Rs. 10 2) Rs. 27 3) Rs. 44.44 4)Rs. 66.67
NEET Master Capsule for Sri Chaitanya Students
CHEMISTRY
Galvanic cells & Nernst equation
20. The value of the reaction quotient Q, for the
cell
Zn s / Zn
2
m
respectively. The value of E 0Cu 2
0.01M Ag 1.25M Ag s is
1) 156
3) 1.25 s 10–2
1) 0.500V
3) 0.650V
2) 125
4) 6.4 s 10–3
21. Calculate the emf of the following concentration
cell at 250C
Ag(s)|AgNO 3 (0.01 M)||AgNO3(0.05M)|Ag(s)
1) - 0.414 V
2) 0.828 V
3) 0.414 V
4) 0.0414 V
22. The equilibrium constant of the following redox
reaction at 298 K is 1 s 108
2Fe 3 (aq.) 2I aq. U 2Fe 2 (aq.) I 2 (s)
If the standard reduction potential fo iodine
becoming iodide is + 0.54 V. What is the standard
reduction potential of Fe3+/Fe2+ ?
1) + 1.006 V
2) - 1.006 V
3) + 0.77 V
4) - .077 V
23. What is the free energy
reaction Li+ + e–
Li ?
D
Given E Li /Li 3.0V,
and T = 298K
1) 289.5 kJ mol–1
2)
3) 32.166 kJ–1 mol–1 4)
m
change for the half
F = 96500 C mol–1
/Cu
will be
2) 0.325V
4) 0.150V
27. The pressure of H 2 required to make the
potential of H2-electrode zero in pure water at
500C is
1) 10 -14
2) 10-7
3) 10+14
4) 10+7
28. The standard reduction potentials for two
reactions are given below:
Ag(s) + Cl-1(aq) ; E0 = 0.21V
AgCl(s) + e-1
Ag+ (aq) + e-1
Ag(s) , E0 = 0.80V
m
m
The value of solubility product (Ksp) of silver
chloride under standard conditions of
temperature is
1) 10 -10
3) 2.3× 10-5
2) 3 × 10-8
4) 18.54
29. How much will be the change in reduction
potential of hydrogen electrode when its
solution initially at pH = 0 is neutralised to
pH=7?
1) increase by 0.059v
–298.5 kJ mol–1
–289500 kJ mol–1
24. For the following cell reaction
Ag / Ag / AgCA / CA / CA 2 / Pt
2) decrease by 0.059v
3) decrease by 0.41v 4) increase by 0.41v
30. Given that
%G 0f (AgCl) 109KJ / mole,
%G 0f (Cl ) 129KJ / mole
%G 0f (Ag ) 78KJ / mole, E 0 of the cell is
1) –0.60V 2) 0.60V
m
2
Cu aq
26. The electrode potential for Cu aq e
Cu s are +0.15V and +0.50V
and Cu aq e
3) 6.0 V
4) 0.5 V
25. The solution of CuSO4 in which copper rod is
immersed is diluted to 10 times. The reduction
electrode potential :
1) Increases by 30 mV
2) Decreases by 30 mV
3) Decreases by 30 V
4) Decreases by 59 mV
NEET Master Capsule for Sri Chaitanya Students
}}m 2I , Eo 0.54V
}}m 2Cl , Eo 1.36 V
e }}
m Mn , Eo 1.5V
e }}
m Fe , Eo 0.77 V
4H
4e }}
m 2H O, Eo 1.23V
I 2 2e Cl 2 2e 3
Mn
Fe
O2
3
2
2
2
Among the following, identify the correct
statement
1) Chloride ion is oxidised by O2
2) Fe+2 ion is oxidised by iodine
3) Mn+2 is oxidised by chlorine
4) Mn+3 oxidises H2O to O2
111
CHEMISTRY
7.
1.
During discharging of Lead storage battery
following reaction takes place
Pb s PbO2 s 2H 2SO 4 m 2PbSO4 s 2H 2 O
If 2.5 amperes of current is drawn for 9.65 min
H2SO4 consumed is
1) 0.75 mole
2) 3.00 mole
3) 0.015 mole
4) 4.5 mole
2.
8.
Efficiency of the following cell is 84%
m
% A s B aq2
A aq2 B s , H
285KJ . Then
the standard electrode potential of the cell will
be
1) 1.24 V 2) 2.40 V 3) 1.10 V 4) 1.20 V
Consider the change in oxidation state of
bromine corresponding to different E.M.F
values as shown in the given diagram
BrO 4
}}}m BrO }}}m BrO
}}}}m Br }}}}m Br
1.82V
1.5V
3
1.595V
1.0652V
2
Then the species undergoing disproportionation
is
4) BrO–
1) BrO3 2) BrO 4 3) Br2
4.
The EMF of the cell
M | M n (0.02) | | H (1M) | H 2(g) (1 atm) ,
Pt at 25°C is 0.81 V. The valency of the metal if
the standard oxidation potential of the metal is
0.76V?
1) 5
5.
2) 2
values, the
On the basis of the following
strongest oxidizing agent is
[Fe(CN)6]3– + e–; E0 = –0.35 V
[Fe(CN)6]4–
Fe2+
Fe3+ + e–; E0 = –0.77 V
}m
1) Fe2+
3) [Fe(CN)6]3–
2) Fe3+
4) [Fe(CN)6]4–
4) 1.968 V
2) 9.0 × 103 g
3) 8.05 × 104 g
4) 2.4 × 105 g
If the E 0cell or a given reaction has a negative
value then which of the following gives the
correct relationships for the value of %G 0 and
Keq?
%G 0 > 0; Keq < 1
3) %G 0 < 0; Keq > 1
%G 0 > 0; Keq > 1
4) %G 0 < 0; Keq < 1
2)
1)
9.
Molar conductivity
0
m
at infinite dilution of
NaCl, HCl and CH 3COONa are 126.4, 425.9
and 91.0 S cm 2 mol –1 respectively m for
CH3COOH will be
1) 425.5 S cm2 mol–1 2) 180.5 S cm2 mol–1
3) 290.8 S cm2 mol–1 4) 390.5 S cm2 mol–1
10. A button cell used in watches functions as
following
Zn(s) + Ag2O(s) + H2O(l) U
2Ag(s) + Zn2+ (aq) + 2OH– (aq)
If half cell potentials are
}}m Zn(s) ; E
m
Ag O(s) + H O(l) + 2e– }}
Zn2+ (aq) + 2e–
2
0
= –0.76 V
2
2Ag(s) + 2OH– (aq); E0 = 0.34 V
The cell potential will be
1) 0.42 V 2) 0.84 V 3) 1.10 V 4) 1.34 V
Standard free energies of formation (in kJ/ mol)
at 298 K are – 237.2, – 394.4 and – 8.2 for
H2O(l), CO2(g) and pentane (g), respectively.
The value of E 0Cell for the pentane-oxygen fuel
cell is
1) 2.0968 V
2) 1.0968 V
3) 0.0968 V
112
4) 3
E0
}}m
6.
3) 4
1) 1.3 × 104 g
V
3.
Al2O3 is reduced by electrolysis at low potentials and high currents. If 4.0 × 104 amperes of
current is passed through molten Al 2 O 3 for
6 hours. What mass of aluminium is produced ?
(Assume 100% current efficiency. Atomic mass
of Al = 27g mol–1)
V
BRAIN STORMING EXERCISE
11. A hydrogen gas electrode is made by dipping
platinum wire in a solution of HCl of pH = 10
and by passing hydrogen gas around the
platinum wire at one atm pressure. The oxidation
potential of electrode would be
1) 0.59 V
2) 0.118 V
3) 1.18 V
4) 0.059 V
NEET Master Capsule for Sri Chaitanya Students
CHEMISTRY
12. When 0.1 mol MnO24 is oxidised the quantity
of electricity required to completely oxidise
MnO24 to MnO 4 is
18. A hypothetical electrochemical cell is shown
below ; A | A (xM)|| B (yM)| B . The emf
measured is + 0.20 V. The cell reaction is
1) 96500 C
2) 2 × 96500 C
1) The cell reaction cannot be predicted
3) 9650 C
4) 96.50 C
2) A + B+
13. The molar conductivity of a 0.5 mol/dm 3
solution of AgNO3 with electrolytic conductivity of 5.76 × 10–3 S cm–1 at 298K
1) 2.88 S
cm2/mol
3) 0.086 S cm2/mol
2) 11.52 S
cm2/mol
3) 220 minutes
4) A+
2) 110 minutes
+
–
Fe + 2Fe3+
+
+ e–
}}m B
}}m 3Fe
2+
will be
1) 1.653 V
2) 0.111 V
3) 0.330 V
4) 1.212 V
20. The equilibrium constant for the reaction :
Cu2+ (aq) + 2Ag :
Cu + 2Ag+ (aq)
}}m
E0
4) 330 minutes
15. The number of electorns delivered at the cathode
during electrolysis by a current of 1 ampere in
60 seconds is
(charge on electron = 1.60 × 10–19 C)
+
19. If E 0Fe2 / Fe = – 0.441 V and E 0Fe3 / Fe2 = 0.771
V, the standard emf of the reaction
4) 28.8 S cm2/mol
14. During the electrolysis of molten sodium
chloride, the time required to produce 0.10 mol
of chlorine gas using a current of 3 amperes is
1) 55 minutes
3) A+
}}m A + B
m A+B
+ B}}
m A; B
+ e }}
= 0.46 V at 298 K is
1) 2.0 × 1010
2) 3.9 × 1015
3) 4.0 × 1010
4) 2.4 × 1010
21. Given :
(i) Cu2+ + 2e–
}}m Cu, E = 0.337V
}}m Cu , E = 0.153V
0
1) 6 × 1023
2) 6 × 1020
(ii) Cu2+ + e–
3) 3.75 × 1020
4) 7.48 × 1023
Electrode potential, E0 for the reaction,
16. An electric current is passed through silver
nitrate solution using silver elecrodes. 10.79 g
of silver was found to be deposited on the
cathode. If the same amount of electricity is
passed through copper sulphate solution using
copper electrodes, the weight of copper
deposited on the cathode is
Cu+ + e–
+
0
}}m Cu, will be
1) 0.38 V
2) 0.52 V
3) 0.90 V
4) 0.30 V
22. For the reduction of silver ions with copper
metal, the standard cell potential is 0.46 V at
250C. The value of standard Gibbs energy %G 0
will be
1) 6.4 g
2) 2.3 g
1) – 89.0 kJ
2) – 89.0 J
3) 12.8 g
4) 3.2 g
3) – 44.5 kJ
4) – 98.0 kJ
17. 4.5 g of Al (atomic mass 27 amu) is deposited
at cathode from Al3+ solution by a certain quantity of charge. The volume of H2 produced at
STP from H + ions in solution by the same
quantity of charge will be
23. Standard electrode potential for Sn4+/Sn2+ couple
is +0.15 V and that for the Cr3+/Cr couple is –
0.74 V. These two cuples in their standard state
are connected to make a cell. The cell potential
will be
1) 11.2 L
2) 44.8 L
1) +1.83 V
2) +1.19 V
3) 5.6 L
4) 22.4 L
3) +0.18 V
4) +0.89 V
NEET Master Capsule for Sri Chaitanya Students
113
CHEMISTRY
KEY SHEET
31) 3
CONCEPTUAL BULLETS
36) 4
32) 3
33) 3
34) 4
35) 2
1) 2
2) 2
3) 4
4) 3
5) 4
6) 4
7) 2
8) 1
9) 3
10) 1
1) 2
2) 3
3) 4
4) 2
5) 2
11) 1
12) 3
13) 2
14) 2
15) 2
6) 1
7) 4
8) 1
9) 1
10) 2
16) 4
17) 1
18) 4
19) 3
20) 2
11) 4
12) 1
13) 1
14) 4
15) 2
21) 4
22) 1
23) 1
24) 4
25) 1
16) 1
17) 2
18) 1
19) 4
20) 4
26) 4
27) 2
28) 1
29) 4
30) 2
21) 4
22) 3
23) 1
24) 2
25) 2
31) 1
32) 4
26) 2
27) 1
28) 1
29) 3
30) 4
Challenger’s Questions
Bull’s Eye Questions
BRAIN STORMING EXERCISE
1) 2
2) 2
3) 4
4) 1
5) 2
6) 3
7) 2
8) 1
9) 3
10) 2
11) 2
12) 4
13) 1
14) 1
15) 1
16) 1
17) 2
18) 3
19) 4
20) 4
21) 2
22) 1
23) 1
24) 1
25) 4
26) 2
27) 3
28) 4
29) 4
30) 2
1) 3
2) 1
3) 4
4) 2
5) 2
6) 2
7) 3
8) 1
9) 4
10) 3
11) 1
12) 3
13) 2
14) 2
15) 3
16) 4
17) 3
18) 2
19) 4
20) 2
21) 2
22) 1
23) 4
fff
114
NEET Master Capsule for Sri Chaitanya Students