Write chemical equations to show what happens when an acid reacts with a (i) metal (ii) base and (iii) carbonate

(i) Zn + 2HCl → ZnCl_2 + H_2; (ii) 2NaOH + H_2SO_4 → Na_2SO_4 + 2H_2O; (iii) Na_2CO_3 + 2HCl → 2NaCl + H_2O + CO_2

ScienceCBSE Class 10 · Board exam 2025, set 31/6/1 · 3 marks · Short answer

CBSE Class 10 Science 2025: question 28(b)

Set in the CBSE Class 10 board exam of 2025, paper 31/6/1, section C, question 28(b), for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q28(b) · 3 marks · Short answerAcids, Bases and Salts

Write chemical equations to show what happens when an acid reacts with a

(i)
metal
0 marks
(ii)
base and
0 marks
(iii)
carbonate
0 marks

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 31/6/1.

Hints

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

Hint 1

Recall the general word equations: acid + metal, acid + base, acid + carbonate.

Hint 2

The products are, in turn, salt + hydrogen; salt + water; salt + water + carbon dioxide.

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.

(i) Acid + metal → salt + hydrogen: $Zn (s) + 2HCl (aq) \to ZnC l_{2} (aq) + H_{2} (g)$
1 mark
(ii) Acid + base → salt + water (neutralisation): $2NaOH (aq) + H_{2} S O_{4} (aq) \to N a_{2} S O_{4} (aq) + 2 H_{2} O (l)$
1 mark
(iii) Acid + carbonate → salt + water + carbon dioxide: $N a_{2} C O_{3} (s) + 2HCl (aq) \to 2NaCl (aq) + H_{2} O (l) + C O_{2} (g)$
1 mark

Answer: (i) $Z n + 2 H C l \to Z n C l_{2} + H_{2}$ ; (ii) $2 N a O H + H_{2} S O_{4} \to N a_{2} S O_{4} + 2 H_{2} O$ ; (iii) $N a_{2} C O_{3} + 2 H C l \to 2 N a C l + H_{2} O + C O_{2}$

Where the marks are

Correct balanced equation for acid with a metal (1 mark)
Correct balanced equation for acid with a base (1 mark)
Correct balanced equation for acid with a carbonate (1 mark)

Revise the chapter

Chapter: Acids, Bases and Salts (notes, formulas, where marks are lost and every past question)

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 paper2025 board paper, set 31/6/1: every question, by section.

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CBSE Class 10 Science 2025: question 28(b)

Hints

Step-by-step solution

Revise the chapter

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