At a particular temperature, the ratio of equivalent conductance to specific conductance of a 0.01 N NaCl solution is

• 10⁵ cm³

• 10³ cm³

• 10 cm³

• 10⁵ cm²

The number of moles of electrons required to deposit 1gm equivalent aluminium (atomic wt. = 27) from a solution of aluminium chloride will be

• 3

• 1

• 4

• 2

At temperature of 298K, the emf of the following electrochemical cell,

Ag (s) | Ag⁺ (0.1 M)|| Zn²⁺ (0.1 M) | Zn (s) will be (Given, E°_cell = -1.562 V)

• -1.532 V

• -1.503 V

• 1.532 V

• -3.06 V

Assertion: Potassium and caesium are used in photoelectric cells.

Reason: Potassium and caesium emit electrons on exposure to light.

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

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

• If the assertion is true but the reason is false.

• If both the assertion and reason are false.

725.

Li occupies a higher position in the electrochemical series of metals as compared to Cu since :

• the standard reduction potential of Li⁺/Li is lower than that of Cu²⁺/Cu

• the standard reduction potential of Cu²⁺/Cu is lower than that of Li⁺/Li

• the standard oxidation potential of Li⁺/Li is lower than that of Cu²⁺/Cu

• Li is smaller in size as compared to Cu

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 1 atm pressure. The oxidation potential of electrode would be

• 0.059 V

• 0.59 V

• 0.118V

• 1.18V

At 25°C molar conductance of 0.1 molar aqueous solution of ammonium hydroxide is 9.54 ohm^-1cm² mol^-1 and at infinite dilution its molar conductance is 238 ohm^-1cm² mol^-1. The degree of ionisation of ammonium hydroxide at the same concentration and temperature is

• 2.080%

• 20.800%

• 4.008%

• 40.800%

A button cell used in watches functions as following

$$\begin{gathered} \mathrm{Zn}\left(\mathrm{s}\right)\hspace{0.17em}+\hspace{0.17em}{\mathrm{Ag}}_2\mathrm{O}\left(\mathrm{s}\right)\hspace{0.17em}+\hspace{0.17em}{\mathrm{H}}_2\mathrm{O} \left(\mathrm{l}\right)\hspace{0.17em} \rightleftharpoons 2\mathrm{Ag}\left(\mathrm{s}\right)\hspace{0.17em}+{\mathrm{Zn}}^{2+}\left(\mathrm{aq}\right)\hspace{0.17em}+\hspace{0.17em}2{\mathrm{OH}}^{-}\left(\mathrm{aq}\right) \\ \mathrm{If}\hspace{0.17em}\mathrm{half}\hspace{0.17em}\mathrm{cell}\hspace{0.17em}\mathrm{potentials}\hspace{0.17em}\mathrm{are}\hspace{0.17em} \\ {\mathrm{Zn}}^{2+}\left(\mathrm{aq}\right)\hspace{0.17em}+\hspace{0.17em}2{\mathrm{e}}^{-} \to \mathrm{Zn}\hspace{0.17em}\left(\mathrm{s}\right); {\mathrm{E}}^{°} = -0.76 \mathrm{V} \\ {\mathrm{Ag}}_2\mathrm{O}\left(\mathrm{s}\right)\hspace{0.17em}+\hspace{0.17em}{\mathrm{H}}_2\mathrm{O} \left(\mathrm{l}\right)\hspace{0.17em}+ 2{\mathrm{e}}^{-}\to 2\mathrm{Ag}\left(\mathrm{s}\right)\hspace{0.17em}+\hspace{0.17em}2{\mathrm{OH}}^{-}\left(\mathrm{aq}\right), {\mathrm{E}}^{°} = 0.34 \mathrm{V} \\ \mathrm{The}\hspace{0.17em}\mathrm{cell}\hspace{0.17em}\mathrm{potential}\hspace{0.17em}\mathrm{will}\hspace{0.17em}\mathrm{be} \end{gathered}$$

• 1.10 V

• 0.42 V

• 0.84 V

• 1.34 V

The quantity of electricity needed to separately electrolyze 1 M solution of ZnSO₄ , AlCl₃ and AgNO₃ completely is in the ratio of

• 2 : 3 : 1

• 2 : 1 : 1

• 2 : 1 : 3

• 2 : 2 : 1

On passing C ampere of current for the time 't' sec through 1 L of 2 (M) CuSO₄ solution (atomic weight of Cu= 63. 5), the amount 'm' of Cu (in gram) deposited on cathode will be

• m = Ct/(63.5 x 96500)

• m = Ct/(31.25 X 96500)

• m = (C x 96500)/(31.25 x t)

• m = (31.25 X C x t)/96500