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A student took a small… (Class 10 Science 2023, Q21A)

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ScienceCBSE Class 10 · Board exam 2023, set 31/4/1 · 2 marks · Very short answer

CBSE Class 10 Science 2023: question 21(A)

Set in the CBSE Class 10 board exam of 2023, paper 31/4/1, section B, question 21(A), for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q21(A) · 2 marks · Very short answerAcids, Bases and Salts

A student took a small amount of copper oxide in a conical flask and added dilute hydrochloric acid to it with constant stirring. He observed a change in colour of the solution.

  1. (i)

    Write the name of the compound formed and its colour.

    1 mark
  2. (ii)

    Write a balanced chemical equation for the reaction involved.

    1 mark

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 31/4/1.

Hints

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

Hint 1

Copper oxide is a basic oxide. What does a basic oxide form with an acid?

Hint 2

The salt formed is the chloride of copper(II). Recall the colour of copper salt solutions.

Hint 3

Balance the chlorine atoms first: one needs two HCl.

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. (i) The compound formed is **copper(II) chloride, ** (cupric chloride).

    ½ mark

  2. The solution becomes blue-green. The black copper oxide dissolves to give this coloured salt solution.

    ½ mark

  3. (ii) A metal oxide reacts with an acid to give a salt and water:

    1 mark

Answer: (i) Copper(II) chloride, blue-green; (ii)

Where the marks are

  • Names copper(II) chloride / (½ mark)
  • States its colour as blue-green (½ mark)
  • Writes the balanced equation (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Acids, Bases and Salts, one at a time, marked against the answer key and marking points.Back to the full paper2023 board paper, set 31/4/1: 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.