At the anode: Pb + SO42−→PbSO4 + 2e−, The anode will be covered with a layer of PbSO4, E = 0.36 V, The standard oxidation potentialof this reaction = 0.36 Volt. At the cathode: PbO2 + 4H+ + SO42− + 2e−→PbSO4 + 2 H2O, The cathode will be covered with a layer of PbSO4, E = 1.69 V, The standard reduction. The state of the battery can be identified by measuring the density of the acid by using a hydrometer (measuring liquid density), When the battery is completely charged, the density of acid = 1.28: 1.30 gm/cm³, When the densityof the acid is decreased to lower than. Using the battery for a long period leads to a decrease the concentration of sulphuric acid as a result of increasing the quantity of water produced from the reaction and also leads to the conversion of cathode material (PbO2) and anode (Pb) to lead (II) sulphate which lead to. Lithium battery is a secondary cell, It is a dry and rechargeable battery used in mobiles, laptop, the modern cars instead of the lead acid battery, it is lighter and stores a large amount of.
