Electrolysis Archives - Page 9 Of 9

Select the correct answer — A compound which during electrolysis in it’s molten state liberates a reddish brown gas at the anode :
1. Sodium chloride
2. Copper (II) oxide
3. Copper (II) sulphate
4. Lead (II) bromide

Lead (II) bromide Reason — During electrolysis of Lead [II] bromide, Br-1 ions are discharged at the anode. Reddish brown fumes are due to bromine vapours.

Aqueous solution of nickel sulphate contains Ni2+ and SO42- ions
(i) Which ion moves towards the cathode?
(ii) What is the product at the anode?

(i) Nickel ion moves towards the cathode. (ii) Product at anode - Nil [Ni2+ are formed]

A metal article is to be electroplated with silver. The electrolyte selected is sodium argentocyanide.
(i) What kind of salt is sodium argentocyanide.
(ii) Why is it preferred to silver nitrate as an electrolyte?
(iii) State one condition to ensure that the deposit is smooth, firm and long lasting.
(iv) Write the reaction taking place at the cathode.
(v) Write the reaction taking place at the anode.

(i) It is a Complex Salt. (ii) Migration of Ag1+ ions from above complex salt soln. is slow compared to that from silver nitrate. Hence, an even deposition of metal silver…

Correct the following statements — Lead bromide conducts electricity.

Molten lead bromide conducts electricity. Reason — Solid lead bromide is a non-conductor of electricity since it's ions are not free but held together by an electrostatic force of attraction. In molten…

Select the correct answer — The aqueous solution of the compound which contains both ions and molecules is:
1. Sulphuric acid
2. Hydrochloric acid
3. Nitric acid
4. Acetic acid

Acetic acid Reason — Acetic acid is a weak electrolyte and particles in a weak electrolyte are ions and unionized molecules.

(A) Sulphur
(B) Silver chloride
(C) Hydrogen chloride
(D) Copper [II] sulphate
(E) Graphite
State which from A to E fits the description — ‘A pink metal is deposited at the cathode during the electrolysis of the soln. of this salt.

(D) Copper [II] sulphate At cathode : Cu2+ + 2e- ⟶ Cu

A soln. contains Mg2+ ions, Fe2+ ions and Cu2+ ions. On passing an electric current through this soln. which ions will be the first to be discharged at the cathode? Write the equation for the cathode reaction.

Cu2+ (Copper ions will get discharged at cathode) Reaction at Cathode: Cu2+ + 2e- ⟶ Cu

Here is an electrode reaction:
Cu ⟶ Cu2+ + 2e-. [i.e. Cu – 2e- ⟶ Cu2+]
At which electrode (anode or cathode) would such a reaction take place ? Is this an example of oxidation or reduction ?

Cu ⟶ Cu2+ + 2e- This reaction takes place at anode. This is an example of oxidation.

During the electrolysis of molten lead bromide, which of the following takes place ?
1. Bromine is released at the cathode
2. Lead is deposited at the anode
3. Bromine ions gain electrons
4. Lead is deposited at the cathode

4. Lead is deposited at the cathode Reaction at cathode : Pb2+ + 2e- ⟶ Pb

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