What is salt bridge? Give its two functions.

A device which is used to connect oxidation half cell and reduction half cell in an electrochemical cell is known as salt bridge. It acts as a junction that connects the anodic and cathodic electrodes in an electrochemical cell. The functions of the salt bridge is: (i) It helps to maintain the neutrality of the two solutions. (ii) It also helps in preventing the cell from taking its reaction to chemical equilibrium.

State Faraday's second law of electrolysis.

When the same quantity of electricity passes through solutions of different electrolytes, the amounts of the substances liberated at the electrodes are directly proportional to their chemical equivalents. The quantity needed to liberate one gram equivalent of a substance if 96 , 495 coulombs and it is known as 'Faraday' F . W 1 W 2 = E 1 E 2 . Where, W 1 & W 2 - amount of the substances. E 1 & E 2 - Chemical equivalents. One Faraday can be defined as the quantity of electricity flowing through an electrolyte that will liberate one gram-equivalent of any substance at any electrode. Faraday’s constant ( F ) is charged in coulombs ( C ) of one mole electrons. We can calculate the value of 1 Faraday by multiplying the charge on one electron which is equal to 1 . 6 × 10 - 19 C by Avogadro’s number ( 6 . 022 × 10 23 ) .

State Faraday's first law of electrolysis.

Faradays first electrolysis Law states that the quantity of reaction taking place in terms of mass of ions formed or discharged from an electrolyte is proportional to the amount of electric current passed. Since, electric current (ampere) is the number of coulombs ( Q ) flowing in one second, Mass of the ions formed or reacted ( m ) α electric current α Q , or m ∝ Q or m = ZQ . Where, Z is a proportionality constant, called the chemical equivalent of the element.

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NEW SYSTEMATIC MODERN CHEMISTRY>Chapter 3 - Electrochemistry>REVIEW EXERCISES>Q 11

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IMPORTANT

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In the cell, $Zn |{Zn}^{2 +} ‖ {Cu}^{2 +}| Cu$ , the negative terminal is

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Important Questions on Electrochemistry

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12th West Bengal Board

IMPORTANT

NEW SYSTEMATIC MODERN CHEMISTRY>Chapter 3 - Electrochemistry>REVIEW EXERCISES>Q 12

Which of the following reaction occurs at the cathode during the charging of lead storage battery?

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NEW SYSTEMATIC MODERN CHEMISTRY>Chapter 3 - Electrochemistry>REVIEW EXERCISES>Q 13

The standard electrode potential

(E^{Θ})

for

{OCl}^{-} / {Cl}^{-}

and

{Cl}^{-} / \frac{1}{2} {Cl}_{2}

respectively are

0.94 V

and

- 1.36 V .

The

E^{Θ}

value for

{OCl}^{-} / \frac{1}{2} {Cl}_{2}

will be

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12th West Bengal Board

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NEW SYSTEMATIC MODERN CHEMISTRY>Chapter 3 - Electrochemistry>REVIEW EXERCISES>Q 14

$E^{Θ}$ for the cell $Zn / {Zn}^{2 +} (aq) ‖ {Cu}^{2 +} (aq) ∣ Cu$ is $1.10 V$ at $25 ° C$ The equilibrium constant for the reaction $Zn + {Cu}^{2 +} (aq) ⇌ Cu + {Zn}^{2 +} (aq)$ is of the order of