The standard oxidation potential E° for the half cell reaction are

$$\begin{gathered} \mathrm{Zn} \to {\mathrm{Zn}}^{2+} + 2{\mathrm{e}}^{-}; \mathrm{E}°= + 0.76 \mathrm{V} \\ \mathrm{Fe}\to {\mathrm{Fe}}^{2+} + 2{\mathrm{e}}^{- }; {\mathrm{E}}^{°}= + 0.41 \mathrm{V} \\ \mathrm{EMF} \mathrm{of} \mathrm{the} \mathrm{cell} \mathrm{reaction} \mathrm{is} \\ \mathrm{Zn} + {\mathrm{Fe}}^{2+} \to {\mathrm{Zn}}^{2+} + \mathrm{Fe} \end{gathered}$$

• - 0.35 V

• + 0.35 V

• 0.17V

• 1.17V.

122.

To observe the effect of concentration on the conductivity of electrolytes of different nature were taken in two vessels A and B. A contains weak electrolyte NH₄OH and B contains strong electrolyte NaCl. In both containers, concentration of respective electrolyte was increased and conductivity observed

•  in A conductivity increases, in B conductivity decreases

• in A conductivity decreases, while in B conductivity increases

• in both A and B conductivity increase

• in both A and B conductivity decreases.

Nausadar is :

• NH₁NO₃

• NH₄Cl

• (NH₄)₂SO₄

• NH₄OH

Anode in the galvanic cell is :

• negative electrode

• positive electrons

• neutral electrode

• none of the above

When Cu reacts with AgNO₃ solution , the reaction takes place is :

• Oxidation of Cu

• Reduction of Cu

• Oxidation of Ag

• Reduction of NO₃^-

The products formed when an aqueous solution of NaBr is electrolysed in a cell having inert electrodes are

• Na and Br₂

• Na and O₂

• H₂, Br₂ and NaOH

• H₂ and O_2.

Ionic mobility of Ag⁺ is ($\mathrm{\lambda }$_Ag⁺ = 5 x 10^-1 ohm^-1 cm² eq^-1) :

• 5.2 x 10^-9

• 2.4 x 10^-9

• 1.52 x 10^-9

• 8.25 x 10^-9

The chemical reaction,
2AgCl _(s) + H_{2 (g)} → 2HCl _(aq) + 2Ag _(s)
taking place in a galvanic cell is represented by the notation

• Pt_(s)| H_{2 (g)}, 1 bar | 1 M KCl _(aq) | AgCl _(s) | Ag _(s)

• Pt_(s)| H_{2 (g)}, 1 bar | 1 M HCl _(aq) | 1M Ag⁺_(aq) | Ag _(s)

• Pt_(s)| H_{2 (g)}, 1 bar | 1 M HCl _(aq) | AgCl _(s) | Ag _(s)

• Pt_(s)| H_{2 (g)}, 1 bar | 1 M KCl _(aq) | Ag _(s) | AgCl _(s)

Assertion: For the Daniel cell, Zn/Zn²⁺||Cu²⁺|Cu with E_cell= 1.1V, application of opposite potential greater than 1.1 V results into flow of electron from cathode to anode.

Reason : Zn is deposited at anode and Cu is  dissolved at cathode.

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

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

• If assertion is true, but reason is false.

• Both assertion and reason are false statements.

Assertion : Fe³⁺ can be used for coagulation of As₂S₃ sol.

Reason: Fe³⁺ reacts with As₂S₃ to give Fe₂S₃.

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

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

• If assertion is true, but reason is false.

• Both assertion and reason are false statements.