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NCERT Class 10 Science Metals and Non-metals: In-text questions (page 46) Solutions
AI-written, checked on 23 Oct 2026
Solutions written by Shishya, checked — not the board's official answers
Step-by-step working for every question of In-text questions (page 46) in NCERT's Class 10 Science book, chapter “Metals and Non-metals”, written by Shishya. Each question is in our own short words; open the NCERT chapter for the exact wording and figures.
How these were checked: the solutions were drafted with AI and then read and corrected on 23 Oct 2026. Every numerical final answer is recomputed from the question's own numbers by a calculator check that runs before each release; proofs and explanations were read, not machine-checked. The NCERT textbook is the authority — if something here disagrees with it, follow the book.
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In-text (page 46) Q1
Why is sodium kept immersed in kerosene oil?
- Sodium is a highly reactive metal that reacts vigorously with oxygen in the air.
- It also reacts violently with moisture or water vapour present in the air to form sodium hydroxide.
- To prevent these unwanted reactions, sodium is stored under kerosene oil.
- Kerosene oil acts as a barrier that isolates sodium from air and moisture.
Answer: Sodium is kept immersed in kerosene oil to prevent it from reacting with oxygen and moisture in the air.
In-text (page 46) Q2
Write equations for the reactions of (i) iron with steam (ii) calcium and potassium with water.
- (i) When iron reacts with steam, it forms iron(II,III) oxide and hydrogen gas.
- (i) The balanced chemical equation is 3Fe + 4H2O → Fe3O4 + 4H2.
why?
A balanced equation has the same number of atoms of each element on both sides, because atoms are neither created nor destroyed in a chemical reaction (law of conservation of mass). Only the numbers in front (coefficients) change, never the formulas.
- (ii) Calcium reacts with water to form calcium hydroxide and hydrogen gas.
- (ii) The balanced chemical equation is Ca + 2H2O → Ca(OH)2 + H2.
why?
A balanced equation has the same number of atoms of each element on both sides, because atoms are neither created nor destroyed in a chemical reaction (law of conservation of mass). Only the numbers in front (coefficients) change, never the formulas.
- (ii) Potassium reacts vigorously with water to form potassium hydroxide and hydrogen gas.
- (ii) The balanced chemical equation is 2K + 2H2O → 2KOH + H2.
why?
A balanced equation has the same number of atoms of each element on both sides, because atoms are neither created nor destroyed in a chemical reaction (law of conservation of mass). Only the numbers in front (coefficients) change, never the formulas.
Answer: (i) 3Fe + 4H2O → Fe3O4 + 4H2; (ii) Ca + 2H2O → Ca(OH)2 + H2 and 2K + 2H2O → 2KOH + H2
In-text (page 46) Q3
Metals A, B, C, D were added to iron(II) sulphate, copper(II) sulphate, zinc sulphate and silver nitrate solutions. A displaced copper only; B displaced iron (and gave no reaction with zinc sulphate); C displaced silver only; D displaced nothing. (i) Which is most reactive? (ii) What happens when B is added to copper(II) sulphate? (iii) Arrange A, B, C, D in decreasing reactivity.
Uses a figure printed in the NCERT book — open the chapter above to see it.
- (i) B displaces iron, which means B is more reactive than iron.
why?
A more reactive metal displaces a less reactive metal from a solution of its salt (reactivity series); a less reactive metal cannot displace a more reactive one.
- A displaces copper, so A is more reactive than copper but less than iron (since it didn't displace iron).
why?
A more reactive metal displaces a less reactive metal from a solution of its salt (reactivity series); a less reactive metal cannot displace a more reactive one.
- C displaces silver, so C is more reactive than silver but less than copper.
why?
A more reactive metal displaces a less reactive metal from a solution of its salt (reactivity series); a less reactive metal cannot displace a more reactive one.
- D displaces nothing, so D is the least reactive.
why?
A more reactive metal displaces a less reactive metal from a solution of its salt (reactivity series); a less reactive metal cannot displace a more reactive one.
- Therefore, B is the most reactive metal.
- (ii) Since B is more reactive than copper, it will displace copper from copper(II) sulphate solution.
why?
A more reactive metal displaces a less reactive metal from a solution of its salt (reactivity series); a less reactive metal cannot displace a more reactive one.
- The reaction is: B + CuSO₄ → BSO₄ + Cu.
- (iii) Based on the displacement reactions, the reactivity order is B > A > C > D.
why?
A more reactive metal displaces a less reactive metal from a solution of its salt (reactivity series); a less reactive metal cannot displace a more reactive one.
Answer: (i) B; (ii) B displaces copper from copper(II) sulphate; (iii) B > A > C > D
- (i) B displaces iron, which means B is more reactive than iron.
In-text (page 46) Q4
Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the reaction of iron with dilute H₂SO₄.
- When dilute hydrochloric acid reacts with a reactive metal, hydrogen gas is produced.
- The general reaction is: Metal + Acid → Salt + Hydrogen gas.
- For the reaction of iron with dilute sulfuric acid, iron reacts to form iron(II) sulfate and hydrogen gas.
- The balanced chemical equation is: Fe + H₂SO₄ → FeSO₄ + H₂.
why?
A balanced equation has the same number of atoms of each element on both sides, because atoms are neither created nor destroyed in a chemical reaction (law of conservation of mass). Only the numbers in front (coefficients) change, never the formulas.
Answer: hydrogen; Fe + H2SO4 → FeSO4 + H2
In-text (page 46) Q5
What do you see when zinc is added to iron(II) sulphate solution? Write the reaction.
- Zinc is more reactive than iron in the reactivity series.
- When zinc is added to iron(II) sulphate, it displaces iron from the solution.
why?
A more reactive metal displaces a less reactive metal from a solution of its salt (reactivity series); a less reactive metal cannot displace a more reactive one.
- The pale green colour of the iron(II) sulphate solution fades (zinc sulphate solution is colourless).
- A grey deposit of iron metal forms on the surface of the zinc.
- The chemical equation for this displacement reaction is Zn + FeSO4 → ZnSO4 + Fe.
Answer: The green solution becomes colourless and grey iron is deposited on the zinc: Zn + FeSO4 → ZnSO4 + Fe
Other exercises in this chapter
- In-text questions (page 40) — 2 questions
- In-text questions (page 49) — 2 questions
- In-text questions (page 53) — 3 questions
- In-text questions (page 55) — 3 questions
- End-of-chapter exercises — 16 questions
← Metals and Non-metals: notes, practice and all exercises
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