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NCERT Class 10 Science Acids, Bases and Salts: In-text questions (page 22) 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 22) in NCERT's Class 10 Science book, chapter “Acids, Bases and Salts”, 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 22) Q1
Why should curd and sour substances not be kept in brass and copper vessels?
- Curd and sour substances contain acids such as lactic acid and citric acid.
- Brass and copper are reactive metals that can react with acids.
- When these acids come in contact with brass or copper, they undergo a chemical reaction.
- This reaction produces toxic metal salts that contaminate the food.
- Consuming food contaminated with these toxic salts can be harmful to health.
Answer: Curd and sour substances should not be kept in brass and copper vessels because the acids in them react with the metals to form toxic salts that can cause food poisoning.
In-text (page 22) Q2
Which gas is usually given off when an acid reacts with a metal? Give an example and a test for the gas.
- When an acid reacts with a metal, hydrogen gas is usually given off.
- For example, zinc reacts with dilute hydrochloric acid to form zinc chloride and hydrogen gas.
- The chemical equation for this reaction is Zn + 2HCl → ZnCl₂ + H₂.
- To test for the gas, bring a burning candle near the mouth of the test tube.
- The gas burns with a characteristic 'pop' sound, confirming it is hydrogen.
Answer: Hydrogen gas; example: Zn + 2HCl → ZnCl₂ + H₂; test: burning candle gives a 'pop' sound.
In-text (page 22) Q3
A metal compound A reacts with dilute hydrochloric acid with effervescence; the gas puts out a burning candle. Write the balanced equation if one product is calcium chloride.
- The gas that puts out a burning candle is carbon dioxide, which is produced when a carbonate reacts with an acid.
- Since one product is calcium chloride, the metal compound A must be calcium carbonate.
- Calcium carbonate reacts with dilute hydrochloric acid to form calcium chloride, water, and carbon dioxide.
- The balanced chemical equation is CaCO3 + 2HCl → CaCl2 + CO2 + H2O.
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: CaCO3 + 2HCl → CaCl2 + CO2 + H2O
Other exercises in this chapter
- In-text questions (page 25) — 6 questions
- In-text questions (page 28) — 4 questions
- In-text questions (page 33) — 5 questions
- End-of-chapter exercises — 15 questions
← Acids, Bases and Salts: notes, practice and all exercises
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