Q3 of 37 Page 1

Read the given passage and answer the questions

A Lead storage battery is the most important type of secondary cell having a lead anode and a grid of lead packed with PbO2 as cathode. A 38% solution of sulphuric acid is used as electrolyte. (Density=1.294 g mL-1) The battery holds 3.5 L of the acid. During the discharge of the battery, the density of H2SO4 falls to 1.139 g mL-1. (20% H2SO4 by mass)


What is the molarity of sulphuric acid before discharge?



We know, Molarity =


Moles of a substance =


Given,


The density of H2SO4 is 1.294gm mL-1


Also, the molecular mass of H2SO4 is 98gm.


So, 1 mL of solution contains 1.294gm H2SO4


∴ 1L (1000mL) of solution contains 1294gm H2SO4


Also, the supplied solution contains 38% H2SO4.


∴ Molarity = =5.018[M]


Thus, the strength is 5.018[M].


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1

Read the given passage and answer the question

A Lead storage battery is the most important type of secondary cell having a lead anode and a grid of lead packed with PbO2 as cathode. A 38% solution of sulphuric acid is used as electrolyte. (Density=1.294 g mL-1) The battery holds 3.5 L of the acid. During the discharge of the battery, the density of H2SO4 falls to 1.139 g mL-1. (20% H2SO4 by mass)


Write the reaction taking place at the cathode when the battery is in use.


 2

Read the given passage and answer the questions

A Lead storage battery is the most important type of secondary cell having a lead anode and a grid of lead packed with PbO2 as cathode. A 38% solution of sulphuric acid is used as electrolyte. (Density=1.294 g mL-1) The battery holds 3.5 L of the acid. During the discharge of the battery, the density of H2SO4 falls to 1.139 g mL-1. (20% H2SO4 by mass)


How much electricity in terms of Faraday is required to carry out the reduction of one mole of PbO2?


 4

Read the given passage and answer the questions

A Lead storage battery is the most important type of secondary cell having a lead anode and a grid of lead packed with PbO2 as cathode. A 38% solution of sulphuric acid is used as electrolyte. (Density=1.294 g mL-1) The battery holds 3.5 L of the acid. During the discharge of the battery, the density of H2SO4 falls to 1.139 g mL-1. (20% H2SO4 by mass)


The lead storage battery is considered a secondary cell. Why?


 5

Read the given passage and answer the question

A Lead storage battery is the most important type of secondary cell having a lead anode and a grid of lead packed with PbO2 as cathode. A 38% solution of sulphuric acid is used as electrolyte. (Density=1.294 g mL-1) The battery holds 3.5 L of the acid. During the discharge of the battery, the density of H2SO4 falls to 1.139 g mL-1. (20% H2SO4 by mass)


Write the products of electrolysis when dilute sulphuric acid is electrolysed using Platinum electrodes.