Balbharati solutions for Chemistry 12th Standard HSC for Maharashtra State Board chapter 5 - Electrochemistry [Latest edition]

Chapter 5: Electrochemistry

Exercise
Exercise [Pages 117 - 119]

Balbharati solutions for Chemistry 12th Standard HSC for Maharashtra State Board Chapter 5 Electrochemistry Exercise [Pages 117 - 119]

Exercise | Q 1.01 | Page 117

Choose the most correct option.

Two solutions have the ratio of their concentrations 0.4 and ratio of their conductivities 0.216. The ratio of their molar conductivities will be ______.

• 0.54

• 574

• 0.0864

• 1.852

Exercise | Q 1.02 | Page 117

Choose the most correct option.

On diluting the solution of an electrolyte _______.

• both ∧ and k increase

• both ∧ and k decrease

• ∧ increases and k decreases

• ∧ decreases and k increases

Exercise | Q 1.03 | Page 117

Choose the most correct option.

1 S m2 mol-1 is equal to _______.

• 10–4 S m2 mol–1

• 104 Ω –1 cm2 mol–1

• 10–2 S cm2 mol–1

• 102 Ω –1 cm2 mol–1

Exercise | Q 1.04 | Page 117

Choose the most correct option.

The standard potential of the cell in which the following reaction occurs:
H2 (g,1 atm) + Cu2+ (1M) → 2H+ (1M) + Cu(s),
("E"_"Cu"^circ = 0.34 "V") is

• - 0.34 V

• 0.34 V

• 0.17 V

• - 0.17 V

Exercise | Q 1.05 | Page 117

Choose the most correct option.

For the cell,

Pb(s) |Pb2+ (1 M)| |Ag+ (1 M)| Ag(s),

if concentration of an ion in the anode compartment is increased by a factor of 10, the emf of the cell will

• increase by 10 V

• increase by 0.0296 V

• decrease by 10 V

• decrease by 0.0296 V

Exercise | Q 1.06 | Page 117

Choose the most correct option.

Consider the half reactions with standard potentials _______.

i. $\ce{Ag^{+}_{ (aq)} + e^- -> Ag_{(s)}E°}$= 0.8 V

ii. $\ce{I_{2(s)} + 2e^- -> 2I^{-}_{ (aq)} E°}$ = 0.53 V

iii. $\ce{Pb^{2+}_{ (aq)} + 2e^- -> pb_{(s)} E°}$= - 0.13 V

iv. $\ce{Fe^{2+} + 2e^- -> Fe_{(s)} E°}$= - 0.44 V

The strongest oxidising and reducing agents respectively are

• Ag and Fe2+

• Ag+ and Fe

• Pb2+ and I

• I2 and Fe2+

Exercise | Q 1.07 | Page 117

Choose the most correct option.

For the reaction:

Ni(s) + Cu2+ (1 M) → Ni2+ (1 M) + Cu(s),

"E"_"cell"^circ = 0.57 V, Δ G° of the reaction is

• 110 kJ

• - 110 kJ

• 55 kJ

• - 55 kJ

Exercise | Q 1.08 | Page 117

Choose the most correct option.

Which of the following is not correct?

• Gibbs energy is an extensive property

• Electrode potential or cell potential is an intensive property

• Electrical work = – ΔG

• If half-reaction is multiplied by a numerical factor, the corresponding E° value is also multiplied by the same factor.

Exercise | Q 1.09 | Page 117

Choose the most correct option.

The oxidation reaction that takes place in lead storage battery during discharge is

• "Pb"_(("aq"))^(2+) + "SO"_(4("aq"))^(2-) -> "PbSO"_(4("s"))

• "PbSO"_(4("s")) + 2"H"_2"O"_(("l")) -> "PbO"_(2("s")) + 4"H"_(("aq"))^+ + "SO"_(4("aq"))^(2-) + 2"e"^-

• "Pb"_("s") + "SO"_(4("aq"))^(2-) -> "PbSO"_(4("s")) + 2"e"^-

• "PbSO"_(4("s")) + 2"e"^-  -> "Pb"_("s") + "SO"_(4("aq"))^(2-)

Exercise | Q 1.1 | Page 118

Choose the most correct option.

Which of the following expressions represent molar conductivity of Al2(SO4)3?

• 3 lambda_("Al"^(3+))^0 + 2lambda _("SO"_4^(2-))^0

• 2 lambda_("Al"^(3+))^0 + 3 lambda _("SO"_4^(2-))^0

• 1//3 lambda_("Al"^(3+))^0 + 1//2lambda _("SO"_4^(2-))^0

• lambda_("Al"^(3+))^0 + lambda _("SO"_4^(2-))^0

Exercise | Q 2.01 | Page 118

What is a cell constant? What are its units? How is it determined experimentally?

Exercise | Q 2.02 | Page 118

Answer the following in one or two sentences.

Write the relationship between conductivity and molar conductivity and hence unit of molar conductivity.

Exercise | Q 2.03 | Page 118

Answer the following in one or two sentences.

Write the electrode reactions during electrolysis of molten KCl.

Exercise | Q 2.04 | Page 118

Answer the following in one or two sentences.

Write any two functions of salt bridge.

Exercise | Q 2.05 | Page 118

Answer the following in one or two sentences.

What is standard cell potential for the reaction

3Ni(s) + 2Al3+ (1 M) → 3Ni2+ (1 M) + 2Al(s), if "E"_("Ni")^circ = - 0.25 V and  "E"_("Al")^circ = - 1.66 V?

Exercise | Q 2.06 | Page 118

Answer the following in one or two sentences.

Write Nernst equation. What part of it represents the correction factor for nonstandard state conditions?

Exercise | Q 2.07 | Page 118

Answer the following in one or two sentences.

Under what conditions the cell potential is called standard cell potential?

Exercise | Q 2.08 | Page 118

Answer the following in one or two sentences.

Formulate a cell from the following electrode reactions:

"Au"_(("aq"))^(3+) + 3"e"^(-) -> "Au"_(("s"))

Mg(s) → "Mg"_(("aq"))^(2+) + 2e-

Exercise | Q 2.09 | Page 118

Answer the following in one or two sentences.

How many electrons would have a total charge of 1 coulomb?

Exercise | Q 2.1 | Page 118

Answer the following in one or two sentences.

What is the significance of the single vertical line and double vertical line in the formulation galvanic cell?

Exercise | Q 3.01 | Page 118

Explain the effect of dilution of the solution on conductivity?

Exercise | Q 3.02 | Page 118

What is a salt bridge?

Exercise | Q 3.03 | Page 118

Write electrode reactions for the electrolysis of aqueous NaCl.

Exercise | Q 3.04 | Page 118

How many moles of electrons are passed when 0.8-ampere current is passed for 1 hour through molten CaCl2?

Exercise | Q 3.05 | Page 118

Construct a galvanic cell from the electrodes Co3+ | Co and Mn2+| Mn.
"E"_"Co"^circ = 1.82 V, "E"_"Mn"^circ = - 1.18 V. Calculate "E"_"cell"^circ

Exercise | Q 3.06 | Page 118

Using the relationship ΔG° of cell reaction and the standard potential associated with it, how will you show that the electrical potential is an intensive property?

Exercise | Q 3.07 | Page 118

Derive the relationship between standard cell potential and equilibrium constant of cell reaction.

Exercise | Q 3.08 | Page 118

It is impossible to measure the potential of a single electrode. Comment.

Exercise | Q 3.09 | Page 118

Why do the cell potential of lead accumulators decrease when it generates electricity? How the cell potential can be increased?

Exercise | Q 3.1 | Page 118

Write the electrode reactions and net cell reaction in NICAD battery.

Exercise | Q 4.01 | Page 118

What is Kohlrausch law of independent migration of ions? How is it useful in obtaining molar conductivity at zero concentration of a weak electrolyte? Explain with an example.

Exercise | Q 4.02 | Page 118

Explain electrolysis of molten NaCl.

Exercise | Q 4.03 | Page 118

What current strength in amperes will be required to produce 2.4 g of Cu from CuSO4 solution in 1 hour? Molar mass of Cu = 63.5 g mol–1.

Exercise | Q 4.04 | Page 118

Equilibrium constant of the reaction,

2"Cu"_(("aq"))^+ -> "Cu"_(("aq"))^(2+) + "Cu"_(("s")) is 1.2 × 106.

What is the standard potential of the cell in which the reaction takes place?

Exercise | Q 4.05 | Page 119

Calculate emf of the cell:

Zn(s) |Zn2+ (0.2 M)||H+ (1.6 M)| H2(g, 1.8 atm)| Pt at 25 °C.

Exercise | Q 4.06 | Page 119

Calculate emf of the cell at 25 °C.

Zn(s) |Zn2+ (0.08 M)| |Cr3+ (0.1 M)| |Cr3+ (0.1 M)| Cr(s)

"E"_"Zn"^circ = - 0.76 V, "E"_"Cr"^circ = - 0.74 V

Exercise | Q 4.07 | Page 119

What is a cell constant? What are its units? How is it determined experimentally?

Exercise | Q 4.08 | Page 119

How will you calculate the moles of electrons passed and mass of the substance produced during electrolysis of a salt solution using reaction stoichiometry?

Exercise | Q 4.09 | Page 119

Write the electrode reactions when lead storage cell generates electricity. What are the anode and cathode and write the electrode reactions during its recharging?

Exercise | Q 4.1 | Page 119

What are anode and cathode of H2 - O2 fuel cell? Name the electrolyte used in it. Write electrode reactions and net cell reaction taking place in the fuel cell.

Exercise | Q 4.11 | Page 119

What are anode and cathode for Leclanche' dry cell? Write electrode reactions and overall cell reaction when it generates electricity.

Exercise | Q 4.12 | Page 119

Identify oxidising agents and arrange them in order of increasing strength under standard state conditions. The standard potentials are given in parenthesis.

Al  (–1.66V), Al3+(–1.66V),  Cl2  (1.36V),  Cd2+ (–0.4V), Fe (–0.44V),  I2 (0.54V),  Br- (1.09V).

Exercise | Q 4.13 | Page 119

Which of the following species are reducing agents? Arrange them in order of increasing strength under standard state conditions. The standard potentials are given in parenthesis.

K (–2.93V),  Br2(1.09V), Mg(–2.36V), Ce3+(1.61V), Ti2+(–0.37V), Ag+ (0.8 V), Ni (–0.23V).

Exercise | Q 4.14 | Page 119

Predict whether the following reaction would occur spontaneously under standard state condition.

"Ca"_(("s")) + "Cd"_(("aq"))^(2+) -> "Ca"_(("aq"))^(2+) + "Cd"_(("s"))

Exercise | Q 4.14 | Page 119

Predict whether the following reaction would occur spontaneously under standard state condition.

2"Br"_(("aq"))^(-) + "Sn"_(("aq"))^(2+) -> "Br"_(2("l")) + "Sn"_(("s"))

Exercise | Q 4.14 | Page 119

Predict whether the following reaction would occur spontaneously under standard state condition.

$\ce{2Ag_{(s)} + Ni^{2+}_{ (aq)} -> 2Ag^{+}_{ (aq)} + Ni_{(s)}}$

Exercise

Balbharati solutions for Chemistry 12th Standard HSC for Maharashtra State Board chapter 5 - Electrochemistry

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