(b) (i) Describe about lithium-ion battery and its uses. (ii) Give reasons for the following (1) Rusting of iron is quicker in saline water than in ordinary water. (2) Aluminium metal cannot be produced by the electrolysis of aqueous solution of aluminium salt.

(b) (i) Describe about lithium-ion battery and its uses. (ii) Give re

1.	(b) (i) Describe about lithium-ion battery and its uses. (ii) Give reasons for the following (1) Rusting of iron is quicker in saline water than in ordinary water. (2) Aluminium metal cannot be produced by the electrolysis of aqueous solution of aluminium salt.
Answer» Solution :(b) (i) 1. Lithium ion battery Anode: Porous GRAPHITE Cathode : Transition metal oxide as `CoO_(2)` Electrolyte: Lithium salt in an organic solvent 2. At the anode oxidation occurs `Li_((s)) RARR Li_((aq))^(+) + E^(-)` At the cathode reduction occurs. `Li^(+) + CoO_(2(s)) + e^(-) rarr LiCoO_(2(s))` 3. Overall reactions `Li_((s)) + CoO_(2) rarr LiCoO_(2(s))` 4. Both electrodes allow `Li^(+)` ions to move in and out of their structures. During discharge the `Li^(+)` ions produced at the anode moves towards cathode through the non-aquaeous electrolyte. 5. When a potential greater than the EMF produced by the cell is applied across the electrode, the cell reaction is reversed and now the `Li^(+)` ions move from cathode to anode where they become embedded on the porous electrode. This is known as intercalation. 6. Uses- This Li-ion battery is used in cellular phones, Laptop computer and digital CAMERA. (ii) 1. It is because in saline water, there are more `H^(+)` ions. Greater the number of `H^(+)` ions, quicker the rusting will take place. 2. It is because aluminium metal is more reactive than hydrogen and it will react with `H_(2)O`.