651.

Cadmium rods are used for which purpose?

• emit electrons

• absorb neutrons

• emit neutrons

• absorb electrons

What is the effect of dilution on the equivalent conductance of strong electrolyte?

• Decrease on dilution

• Remains unchanged

• Increase on dilution

• None of the above

How many moles of Pt may be deposited on the cathode when 0.80 F of electricity is passed through a 1.0 M solution of Pt⁴⁺ ?

• 1.0 mol

• 0.20 mol

• 0.40 mol

• 0.80 mol

Calculate ${\wedge }_{\mathrm{HOAc}}^{\infty }$ (in S cm² mol^-1) using appropriate molar conductances of the electrolytes listed in the given table

Electrolyte	KCl	KNO3	HCl	NaOAc	NaCl
${\wedge }^{\infty }$ (S cm2 mol-1)	149.9	145.0	426.2	91.0	126.5

at infinite dilution in H₂O at 25$°$C

• 517.2

• 305.0

• 390.7

• 217.5

An aqueous solution containing 6.5 g of NaCl of 90 purity was subjected to electrolysis. After the complete electrolysis, the solution was evaporated to get solid NaOH. The volume of 1 M acetic acid required to neutralise NaOH obtained above is :

• 1000 cm³

• 2000 cm³

• 100 cm³

• 200 cm³

Corrosion of iron is essentially an electrochemical phenomenon where the cell reactions are :

• Fe is oxidised to Fe²⁺ and dissolved oxygen in water is reduced to OH^-

• Fe is oxidised to Fe³⁺ and H₂O is reduced to ${\mathrm{O}}_2^{2-}$

• Fe is oxidised to Fe²⁺ and H₂O is reduced to ${\mathrm{O}}_2^{2-}$

• Fe is oxidised to Fe²⁺ and H₂O is reduced to O₂

On the basis of standard electrode potential of redox couples given below, find out which of the following is the strongest oxidising agent.

(E$°$ values : Fe³⁺ | Fe²⁺ = +0.77 V; I_2(s) | I^- = +0.54 V; Cu²⁺ | Cu = +0.34 V; Ag⁺ | Ag = +0.80 V)

• Fe³⁺

• I_2(s)

• Cu²⁺

• Ag⁺

Assertion : If standard reduction potential for the reaction Ag⁺ + e^- $\to$ Ag is 0.80 volt, then for the reaction 2Ag⁺ + 2e^- $\to$ 2Ag, it will be 1.60 volt.

Reason: If concentration of Ag⁺ ions is doubled, the standard electrode potential is also doubled.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false.

• If both assertion and reason are false.

How many Faradays of electricity are required for the given reaction to occur ?

Mn${\mathrm{O}}_4^{-} \to$Mn²⁺

• 5 F

• 3 F

• 1 F

• 7 F

A conductivity cell has a cell constant of 0.5 cm^-1. This cell when filled with 0.01 M NaCl solution has a resistance of 384 ohms at 25°C. Calculate the equivalent conductance of the given solution.

• 130.2 ${\Omega }^{-1}$ cm² (g eq)^-1

• 137.4 ${\Omega }^{-1}$ cm² (g eq)^-1

• 154.6 ${\Omega }^{-1}$ cm² (g eq)^-1

• 169.2 ${\Omega }^{-1}$ cm² (g eq)^-1