Skip to content

Draw a labelled diagram to… (Class 10 Science 2024, Q28)

questionbuddy.in/q/cbse-10-science-2024-31-2-1-q28-draw-labelled-diagram-electrolytic-refining

ScienceCBSE Class 10 · Board exam 2024, set 31/2/1 · 3 marks · Diagram

CBSE Class 10 Science 2024: question 28

Set in the CBSE Class 10 board exam of 2024, paper 31/2/1, section C, question 28, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q28 · 3 marks · DiagramMetals and Non-metals

Draw a labelled diagram to show electrolytic refining of copper. State what happens when electric current is passed through the electrolyte taken in this case.

Figure in the paper: Labelled diagram required of an electrolytic refining cell for copper (impure copper anode, pure copper cathode, copper sulphate electrolyte, battery), to be drawn by the candidate. See it in the official paper.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 31/2/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

The impure metal is made one electrode and a thin strip of pure metal the other.

Hint 2

The electrolyte is a solution of a salt of the same metal; the anode is joined to the positive terminal.

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. Diagram (described): Draw a tank containing acidified copper sulphate solution. Dip two copper rods into it. Join a thick block of impure copper to the positive terminal of a battery (through a key); this is the anode. Join a thin strip of pure copper to the negative terminal; this is the cathode. Show anode mud (impurities) settling at the bottom below the anode.

    1 mark

  2. Labels: Anode (impure copper), cathode (pure copper), electrolyte (acidified copper sulphate solution). Anode mud may also be labelled.

    1 mark

  3. What happens: When current is passed, copper from the impure anode dissolves into the electrolyte as ions. An equal amount of pure copper from the solution is deposited on the cathode. Soluble impurities stay in the solution and insoluble impurities settle as anode mud.
    At anode:
    At cathode:

    1 mark

Answer: Impure Cu anode, pure Cu cathode, acidified electrolyte. Cu dissolves from the anode and an equal amount of pure Cu is deposited on the cathode; impurities form anode mud.

Where the marks are

  • Correct diagram of the refining cell (1 mark)
  • Labels for the electrodes and the electrolyte (1 mark)
  • Explains that Cu dissolves at the anode and pure Cu deposits at the cathode, or writes the two electrode equations (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Metals and Non-metals, one at a time, marked against the answer key and marking points.Back to the full paper2024 board paper, set 31/2/1: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.