Chemistry
Observe the diagram given below used in the electrolysis of aqueous CuSO4 solution. Study the diagram and answer the following.
(a) Write the equation for the reactions that is occurring at anode and cathode.
(b) State two appropriate observations for the given electrolysis reaction.
(c) Why does the blue colour of Cu2+ ions in the electrolytic solution fades slowly? Explain.
Electrolysis
ICSE
1 Like
Answer
(a) Reaction at cathode:
Cu2+ + 2e- ⟶ Cu
Reaction at anode:
OH1- - 1e- ⟶ OH x 4
4OH ⟶ 2H2O + O2
(b) Two observations for this electrolysis are:
- Pink or reddish brown copper is deposited at the cathode.
- The blue colour of copper sulphate solution slowly fades away and it becomes colourless.
(c) As the Cu2+ ions are discharged at the cathode and deposited as copper metal, there is a decrease in Cu2+ ions in the solution. This causes the blue colour to fade slowly and finally the solution becomes colourless as soon as Cu2+ ions are finished.
Answered By
2 Likes
Related Questions
Identify the following.
(a) The acid that is present in vinegar.
(b) A metal which catches fire, when kept in open air.
(c) A sweet smelling compound formed when ethanol reacts with ethanoic acid.
(d) A catalyst used in Haber's process.
(e) An organic compound used for ripening and preservation of fruits.
The molecular mass of CO2 and O2 are approximately 44 and 32 respectively. Which of the following statements regarding the mass of oxygen and number of molecules of oxygen is correct?
P. The mass of oxygen in 2.24 litres of CO2 is 3.2 g
Q. The number of molecules of oxygen present in it is 6.022 x 1023
- Only P
- Only Q
- Both P and Q
- Neither P nor Q
Match the following Column I with column II
Column I Column II (a) Vanadium pentaoxide 1. Preparation of a gas used in ripening of the fruits. (b) Acetic acid 2. Contains only ions (c) Calcium carbide 3. Low melting point (d) Dil. hydrochloric acid 4. Vinegar (e) Covalent compound 5. Sulphuric acid Complete the following by choosing the correct answer from the bracket.
(a) Alkenes differ from alkanes due to the presence of …………… (double/single) bonds.
(b) Down the group, ionisation potential …………… (increases /decreases).
(c) By dissolving aluminium oxide in cryolite a …………… (conducting/non-conducting) solution is produced.
(d) The catalyst used for conversion of ethene to ethane is commonly …………… (iron/nickel).
(e) The gas released when sodium carbonate is added to a solution of sulphur dioxide is …………… (CO2/SO3)