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MnO_2 + x\ HCl → MnCl_2 + y\… (Class 10 Science 2023, Q3)

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ScienceCBSE Class 10 · Board exam 2023, set 31/1/1 · 1 mark · MCQ

CBSE Class 10 Science 2023: question 3

Set in the CBSE Class 10 board exam of 2023, paper 31/1/1, section A, question 3, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q3 · 1 mark · MCQChemical Reactions and Equations


In order to balance the above chemical equation, the values of , y and z respectively are :

  1. (A)6, 2, 2
  2. (B)4, 1, 2
  3. (C)4, 2, 1
  4. (D)2, 2, 1

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

Hints

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

Hint 1

Start with the oxygen atoms, which appear only in and water.

Hint 2

Once the number of water molecules is fixed, the hydrogen atoms tell you how much HCl is needed.

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. Balance O first. There are 2 O on the left, so (). Then there are 4 H on the right, so ().

  2. Cl: there are 4 on the left. On the right, has 2, so must supply the other 2, giving .

  3. Balanced equation: , so , which is option (C).

    1 mark

Answer: x = 4, y = 2, z = 1; option (C)

Where the marks are

  • Correct values 4, 2, 1, option (C) (1 mark)

Revise the chapter

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