During electrolysis of fused lead bromide, __________ is deposited at the cathode.
(a) State observation at the anode when aqueous copper sulphate solution is electrolysed using copper electrodes.
(b) During electrolysis of molten lead bromide, graphite anode is preferred to other electrodes. Give reason.
(c) Electrolysis of molten lead bromide is considered to be a redox reaction. Give reason.
(a) Here is an electrode reaction :
Cu→Cu2++2e−. At which electrode (anode or cathode) would such a reaction take place? Is this an example of oxidation or reduction ?
(b) A solution contains magnesium ions (Mg2+), iron (II) ions Fe2+ and copper ions Cu2+. On passing an electric current through this solution, which ions will be the first to be discharged at the cathode? Write the equation for the cathode reaction.
(c) Why is carbon tetrachloride, which is a liquid, a non-electrolyte ?
(d) During the electrolysis of molten lead bromide, which of the following takes place ?
A. Bromine is released at the cathode,
B. Lead is deposited at the anode,
C. Bromine ions gain electrons,
D. Lead is deposited at the cathode.
Give reasons for the following :
(a) Electrolysis of molten lead bromide is considered to be a reaction in which oxidation and reduction go side, i.e., a redox reaction.
(b) The blue colour of aqueous copper sulphate fades when it is electrolysed using platinum electrodes.
(c) Lead bromide undergoes electrolytic dissociation in the molten state but is a non- electrolyte in the solid state.
(d) Aluminium is extracted from its oxide by electrolytic reduction and not by conventional reducing agents.
(e) The ratio hydrogen and oxygen formed at the cathode and anode is 2: 1 by volume.
(f) In the electrolysis of acidified water, dilute sulphuric acid is preferred to dilute nitric acid for acidification.
(g) Ammonia is unionised in the gaseous state but in the aqueous solution, it is a weak electrolyte.
(h) A graphite anode is preferred to other inert electrodes during electrolysis of fused lead bromide.
(i) For electroplating with silver, silver nitrate is not used as the electrolyte.
(j) Carbon tetrachloride is a liquid but does not conduct an electrolyte.
(k) Potassium is not extracted by electrolysis of its aqueous salt solution.