(a) State one appropriate observation for: Electricity is passed through molten lead bromide.

(b) State which of these will act as a non-electrolyte

(i) Liquid carbon tetrachloride

(ii) Acetic acid

(iii) Sodium hydroxide aqueous solution

(iv) Potassium chloride aqueous solution

(c) Copper sulphate soln. is electrolysed using copper electrodes.

(i) Which electrode to your left or right is known as the oxidising electrode and why ?

(ii) Write the equation representing the reaction that occurs.

(iii) State two appropriate observations for the above electrolysis reaction.

(d) Identify : A gas which does not conduct electricity in the liquid state but conducts electricity when dissolved in water.

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Solution

C)
i) The right electrode is known as an oxidising electrode because copper ion gains electron to form copper metal. i.e, reduction takes place.

ii) At cathode: Cu²⁺ +2e^- -----> Cu

At anode: Cu--------> Cu²⁺+2e^-
iii)
* Reddish brown metal copper is deposited at the cathode.

*) Blue colour of electrolytic solution I,e. CuSO₄ does not fade during the process.
d)
Liquified HCl gas

Pure Liquid or gaseous hydrogen chloride is not ionic in nature. It is purely covalent i.e. HCl do not have tendency to form ion which can conduct electricity.Thus absence of free flow of ions do not allow HCl solution to conduct but as the HCl is dissolved in water, it start conducting electricity due to presence of free ion of H⁺ and Cl^-

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Similar questions

(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.

(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.

(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.

Q. State your observations for the following electrolytic reactions:
(a) Solid copper sulphate is electrolysed between platinum electrodes.
(b) Aqueous copper sulphate is electrolysed between platinum electrodes.
(c) Aqueous copper sulphate is electrolysed between copper electrodes.

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.

(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.

Q. Give reasons why :
(i) Sodium Chloride will conduct electricity only in fused or aqueous solution state.
(ii) In the electroplating of an article with silver, the electrolyte sodium argento-cyanide solution is preferred over silver nitrate solution.
(iii) Although copper is a good conductor of electricity, it is a non-electrolyte.

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