A cell, with cell constant 0.4 cm-1, has the resistance of 40 ohm

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 Multiple Choice QuestionsMultiple Choice Questions

481.

At 298 K the molar conductivities at infinite dilution (Λm°) of NH4Cl, KOH and KCl are 152.8, 272.6 and 149.8 S cm2 mol-1respectively. The Λm° of NH4OH in Scm2 mol-1 and % dissociation of 0.01 M NH4OH with Λm= 25.1 S cm2 mol-1 at the same temperature are

  • 275.6, 0.91

  • 275.6, 91

  • 266.6, 96

  • 30, 84


482.

The products obtained at the cathode and anode respectively during the electrolysis of aqueous K2SOsolution using platinum electrodes are

  • O2, H2

  • H2, O2

  • H2, SO2

  • K2, SO2


483.

Same amount of electricity is passed through aqueous solutions of AgNO3 and CuSO4. The number of Ag and Cu atoms deposited are x and y respectively. The correct  relationship between x and y is

  • x <y 

  • x= 2y

  • x = y

  • y = 2x


484.

In the acidic solution of copper sulphate and alkaline solution of copper cyanide respectively same electric current is flown for a definite time, which of the following statement is correct for this?

  • Amount of copper deposited in both the solution is the same

  • Amount of copper deposited in alkaline copper cyanide solution is less

  • Amount of copper deposited in acidic copper sulphate solution is less

  • None of the above


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485.

What is the emf of the cell, whose half cells are given below

Mg2+ + 2e- → Mg(s) E =-2.37 V

Cu2+ + 2e- → Cu(s) E =+0.34 V

  • -2.30V

  • 1.336V

  • 2.17V

  • 2.93V


486.

Zn | Zn2+C = 1 || Cu2+C = 1 | Cu

If the standard reduction potential of zinc electrode and copper half cell is -0.76 V and 0.34 V respectively then the emf will be

  • 1.1 V

  • 1.4 V

  • 1.34 V

  • None of these


487.

Rusting on iron needs

  • dry air

  • air and water

  • distilled water and carbon dioxide

  • oxygen and carbon dioxide


488.

In galvanic cell, the salt bridge is used to

  • complete the circuit

  • reduce the electric resistance in the cell

  • separate cathode from anode

  • carry salts for the chemical reaction


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489.

A cell, with cell constant 0.4 cm-1, has the resistance of 40 ohm of a 0.01 M solution of an electrolyte, then the molar conductivity in ohm-1 cm2 mol-1 will be

  • 104

  • 103

  • 102

  • 1


B.

103

Cell constant = 0.4 cm-1

Resistance = 40 ohm

 Conductivity = 140 ohm-1

Concentration of solution = 0.01 M

Specific conductivity = conductivity × cell constant

                              = 140 ohm-1 × 0.4 cm-1

                              = 0.01 ohm-1 cm-1

   Molar conductivity = Specific conductivity × 1000Concentration (molarity)

                              = 0.01 × 10000.01

                              = 1000 ohm-1 cm2 mol-1


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490.

If the standard elelctrode potential for the cell Zn | Zn2+ (aq) || Cu2+ (aq) | Cu is 1.10 V, then the maximum work done by this cell will be

  • -106.15 kJ

  • -212.30 kJ

  • -318.45 kJ

  • -424.60 kJ


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