Consider the following chemical equation I and II I. Mg + 2HCl → MgCl_2 + H_2 II. NaOH + HCl → NaCl + H_2O The correct statement about these equations is (A) 'I' is a displacement reaction and 'II' is a decomposition reaction. (B) 'I' is a displacement reaction and 'II' is double displacement reaction. (C) Both 'I' and 'II' are displacement reactions. (D) Both 'I' and 'II' are double-displacement reactions.

ScienceCBSE Class 10 · Board exam 2023, set 31/6/1 · 1 mark · MCQ

CBSE Class 10 Science 2023: question 12

Set in the CBSE Class 10 board exam of 2023, paper 31/6/1, section A, question 12, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q12 · 1 mark · MCQChemical Reactions and Equations

Consider the following chemical equation I and II

I. $Mg + 2HCl \to MgC l_{2} + H_{2}$

II. $NaOH + HCl \to NaCl + H_{2} O$

The correct statement about these equations is

(A)'I' is a displacement reaction and 'II' is a decomposition reaction.
(B)'I' is a displacement reaction and 'II' is double displacement reaction.
(C)Both 'I' and 'II' are displacement reactions.
(D)Both 'I' and 'II' are double-displacement reactions.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 31/6/1.

Hints

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

Hint 1

In which reaction does one element replace another?

Hint 2

In which reaction do two compounds swap ions?

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.

In I, Mg displaces H from HCl, so it is a displacement reaction.
½ mark
In II, NaOH and HCl exchange ions to form NaCl and water (neutralisation), so it is a double displacement reaction. Hence the answer is option (B).
½ mark

Answer: Option (B)

Where the marks are

I displacement, II double displacement (1 mark)

Revise the chapter

Chapter: Chemical Reactions and Equations (notes, formulas, where marks are lost and every past question)

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 31/6/1: every question, by section.

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CBSE Class 10 Science 2023: question 12

Hints

Step-by-step solution

Revise the chapter

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