Question

(a) The observation seen when fused lead bromide is electrolysed is :

(i) A silver grey deposit at an anode and a reddish brown deposit at the cathode.

(ii) A silver grey deposit at the cathode and a reddish brown deposit at the anode.

(iii) A silver grey deposit at the cathode and reddish brown fumes at the anode.

(iv) Silver grey fumes at anode reddish brown fumes at the cathode.

(b) During electroplating an article with silver, the electrolyte used is :

(i) Silver nitrate solution

(ii) Silver cyanide solution

(iii) Sodium argentocyanide solution

(iv) Nickel sulphate solution.

(c) Give one word or phrase for electrolytic deposition of a superior metal on a baser metal.

(d) State your observation: At the cathode when acidified aqueous copper sulphate solution is electrolysed with copper electrodes.

(e) State which electrode: anode or cathode is the oxidising electrode. Give a reason for the same.

(f) Name the king of particle present in :

(i) Sodium hydroxide soln.

(ii) Carbonic acid

(iii) Sugar soln.

(g) $M_{2}O$ is the oxide of a metal 'M' which is above hydrogen in the activity series. $M_{2}O$ when dissolved in water forms the corresponding hydroxide which is a good conductor of electricity.

(i) State the reaction taking place at the cathode

(ii) Name the product at the anode.

Answer 1

a) (iii) A silver-grey deposit at the cathode and reddish brown deposits at the anode.

b) (iii) Sodium argentocynaide solution
c)Electroplating
d) The blue colour of aq. copper sulphate remains unchanged.

f)

i) Sodium hydroxide solution:- Ions i.e $N{a}^{+}$ and $O{H}^{-}$

ii) Carbonic acid: Ions i.e $H^{+}$ and $C{O}_3^{2-}$

iii) Sugar solution:- Molecules $C_{12}{H}_{22}{O}_{11}$
_g)
i) $M^{+}+e^{-}⟶M$ (reduction occur)
ii) Oxygen gas