Skip to content

Observe the following… (Class 12 Chemistry SQP 2024-25, Q19)

questionbuddy.in/q/cbse-12-chemistry-2024-25-sqp-q19-observe-cell-represent-cell-name

ChemistryCBSE Class 12 · Sample paper, session 2024-25 · 2 marks · Very short answer

CBSE Class 12 Chemistry sample paper 2024-25: question 19

From the official CBSE sample question paper for 2024-25, section B, question 19, for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q19 · 2 marks · Very short answerElectrochemistry

Observe the following cell and answer the questions that follow:
a. Represent the cell shown in the figure. (1)
b. Name the carriers of the current in the salt bridge (½)
c. Write the reaction taking place at the anode. (½)

Figure in the paper: Galvanic cell: two beakers joined by an inverted U-shaped salt bridge. Left beaker contains XCl solution with electrode X; right beaker contains YCl2 solution with electrode Y. Electrodes are connected externally through a galvanometer G. See it in the official paper.

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2024-25.

Hints

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

Hint 1

In cell notation, the anode (oxidation) is written on the left.

Hint 2

Electrons flow in the wire. What moves inside the salt bridge?

Hint 3

Oxidation means loss of electrons by the metal electrode.

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. (a) Y is oxidised (anode) and X⁺ is reduced (cathode). Writing the anode on the left:

    1 mark

  2. (b) The current in the salt bridge is carried by ions: the cations and anions of the inert electrolyte in it (e.g. and or from KCl/KNO₃). They migrate to keep both solutions electrically neutral.

    ½ mark

  3. (c) Anode (oxidation):

    ½ mark

Answer: (a) Y(s)|Y²⁺(aq)||X⁺(aq)|X(s); (b) ions of the salt-bridge electrolyte; (c) Y(s) → Y²⁺(aq) + 2e⁻

Where the marks are

  • Correct cell notation with anode on the left and salt bridge shown as || (1 mark)
  • Ions (e.g. K⁺, Cl⁻/NO₃⁻) carry current in the salt bridge (½ mark)
  • Anode half-reaction Y → Y²⁺ + 2e⁻ (½ mark)

Revise the chapter

  • Chapter: Electrochemistry (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Electrochemistry, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2024-25: 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.