QQuestion
The following sketch represents the electroplating of an Iron cup with Nickel metal. Study the diagram and answer the following questions:
(a) During electroplating the iron cup is placed at the cathode. Why?
(b) Name the ion that must be present in the electrolyte.
(c) State one condition that is necessary to ensure that the deposit is smooth, firm and even.
(d) Write the reaction taking place at the cathode.
(e) What change would you observe at the anode?
✓Answer
(a) In electroplating, the cathode is the electrode where reduction (gain of electrons) occurs. The iron cup is placed at the cathode because the metal ions from the electrolyte will be reduced and deposit onto the iron cup. This process coats the iron cup with a layer of metal, achieving the plating effect.
(b) Ni2+ must be present in the electrolyte.
(c) A low current for a longer time should be used as longer time and low current initiates a thicker, uniform deposit.
(d) Ni2+ + 2e– → Ni
(e) The Nickel plate is gradually dissolved as ions in solution.
Related Questions
More ICSE Moderate level questions
State the terms for the following: (a) The group obtained by removing one hydrogen atom from the parent alkane. (b) Two metal plates or wires through which the current enters and leaves the electrolytic cell. (c) The amount of substance which contains the same number of units as the number of atoms in carbon-12. (d) The tendency of an atom to pull a shared pair of electrons towards itself in a compound. (e) The formula which represents the simplest ratio between the atoms of elements present in a compound.
Complete the following sentences by choosing the correct answer from the brackets: (a) The salt that can be prepared by Direct Combination is ............... . [FeCl3 / FeCl2] (b) The metallic oxide which can be reduced by using common reducing agents is ............... . [Fe2O3 / Al2O3] (c) The metal nitrate which on thermal decomposition forms a black residue is ............... . [zinc nitrate / copper nitrate] (d) During the electrolysis of copper sulphate solution, if ............... is used as electrodes, the colour of the electrolyte does not fade. [copper / platinum] (e) The process of heating the concentrated ore in a limited supply or absence of air is ............... . [roasting / calcination]
X - HCl ⇋ H1+ + Cl- (in solution state) Y - PbBr2 ⇋ Pb2+ + 2Br1- (in molten state) From the above reactions X or Y, identify the reaction which exhibits: (a) electrolytic dissociation (b) ionization
Match the Column A with Column B: Column A Column B (a) Sodium chloride 1. has two shared pair of electrons (b) Methane 2. has high melting and boiling points (c) Hydrogen chloride gas 3. a greenhouse gas (d) Oxidation reaction 4. has low melting and boiling points (e) Water 5. Zn − 2e− ⟶ Zn2+ 6. S + 2e− ⟶ S2−
The following sketch illustrates the process of conversion of Alumina to Aluminium: [5] Study the diagram and answer the following: (a) Name the constituent of the electrolyte mixture which has a divalent metal in it. (b) Name the powdered substance ‘X’ sprinkled on the surface of the electrolyte mixture. (c) What is the name of the process? (d) Write the reactions taking place at the electrodes ‘Y’ (anode) and ‘Z’ (cathode) respectively.
Complete the following sentences by choosing the correct option from the brackets: (a) The oxide that dissolves in caustic potash (KOH) is ............... . [ZnO / CuO] (b) The reaction that takes place at the anode during the electrolysis of molten lead bromide is ............... . [2Br − 2e− ⟶ 2Br− / 2Br− − 2e− ⟶ Br2] (c) The volume occupied by 8 grams of oxygen gas at STP is ............... litres. [5.6 / 8.96] [Atomic weight of O = 16] (d) ............... does not give hydrogen gas when it reacts with cold and very dilute nitric acid. [Cu / Mn] (e) ............... is a polar covalent compound. [HCl / CCl4]
Complete the following sentences by choosing the correct word(s) from the brackets: (a) ............... solution forms a coloured precipitate with ammonium hydroxide which is soluble in excess of ammonium hydroxide. [Ferrous chloride / Copper nitrate] (b) Zinc blende is converted to zinc oxide by ................ [Calcination / Roasting] (c) ............... conducts electricity by the movement of ions. [Molten iron / Molten sodium chloride] (d) The reaction that takes place at the anode during the electrolysis of aqueous Sodium argentocyanide with silver electrodes is ................ [Ag ⟶ Ag+ + e-/ Ag+ + e- ⟶ Ag] (e) The salt formed when ZnO reacts with hot concentrated NaOH is ............... . [sodium zincate / zinc hydroxide]
Match Column A with Column B: Column A Column B (a) CuO + C ⟶ Cu + CO 1. Oxidation (b) Al3+ + 3e− ⟶ Al 2. Ionisation (c) PbBr2 ⟶ Pb2+ + 2Br1− 3. Reduction (d) 2O2− − 2e− ⟶ O2 4. Redox (e) HCl ⟶ H+ + Cl1− 5. Electrolytic dissociation
Arrange the following according to the instructions given in brackets: (a) C2H2, C3H6, CH4, C2H4 (In the increasing order of the molecular weight) (b) Cu2+, Na+, Zn2+, Ag+ (The order of Preferential discharge at the cathode)
Answer the following with reference to the electrolytic refining of copper: (a) What is used as the anode? (b) Where is pure copper deposited? (c) Write the cathode reaction.
Fill in the blanks by choosing the correct answer from the brackets: (a) During electrolysis, the compound ............... in its molten state liberates reddish brown fumes at the anode. [NaCl/PbBr2] (b) The ion which could be discharged most readily during electrolysis is ............... [Fe2+/Cu2+]
K, L and M are beakers containing three different solutions as shown below. Name the beaker which: (a) contains only ions. (b) contains only molecules. (c) has pH less than 7.