$13$Read the passage given below and answer the questions that follow: Oxidation-reduction reactions are commonly known as redox reactions. They involve transfer of electrons from one species to another. In a spontaneous reaction, energy is released which can be used to do useful work. The reaction is split into two half reactions. Two different containers are used and a wire is used to drive the electrons from one side to the other and a Voltaic/Galvanic cell is created. It is an electrochemical cell that uses spontaneous redox reactions to generate electricity. A salt bridge also connects to the half cells. The reading of the voltmeter gives the cell voltage or cell potential or electromotive force. If $\displaystyle \mathrm{E}_{\text {cell }}^{\mathrm{o}}$ is positive the reaction is spontaneous and if it is negative the reaction is non-spontaneous and is referred to as electrolytic cell. Electrolysis refers to the decomposition of a substance by an electric current. One mole of electric charge when passed through a cell will discharge half a mole of a divalent metal ion such as $\displaystyle \mathrm{Cu}^{2+}$. This was first formulated by Faraday in the form of laws of electrolysis. The conductance of material is the property of materials due to which a material allows the flow of ions through itself and thus conducts electricity. Conductivity is represented by k and it depends upon nature and concentration of electrolyte, temperature etc. A more common term molar conductivity of a solution at a given concentration is conductance of the volume of solution containing one mole of electrolyte kept between two electrodes with the unit area of cross-section and distance of unit length. Limiting molar conductivity of weak electrolytes cannot be obtained graphically. 2022_CBSE_Chemistry_Set_Region5_Subset_Set1_Q12_SECTION-C__p5_23

2022_CBSE_Chemistry_Set_Region5_Subset_Set1_Q12_SECTION-C__p5_23

(a) Is silver plate the anode or cathode? 1 (b) What will happen if the salt bridge is removed? 1 (c) When does electrochemical cell behaves like an electrolytic cell? 1 (d) (i) What will happen to the concentration of $\displaystyle \mathrm{Zn}^{2+}$ and $\displaystyle \mathrm{Ag}^{+}$when $\displaystyle \mathrm{E}_{\text {cell }}=0$. (ii) Why does conductivity of a solution decreases with dilution?

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(d) The molar conductivity of a 1.5 M solution of an electrolyte is found to be $\displaystyle 138.9 \mathrm{~S} \mathrm{~cm}^{2} \mathrm{~mol}^{-1}$. Calculate the conductivity of this solution.

Chemistry · Electrochemistry · Electrochemical Cells