Chapter 1 – Chemical Reactions and Equations
NCERT Class 10 Science Chapter 1 – Chemical Reactions and Equations NCERT Solutions (Quick and Exam-oriented) --- 1. Very short answers (1 mark) Q1. What is a chemical reaction? Ans. A process in which one or more substances change to form new substances. Q2. Why should chemical equations be balanced? Ans. To satisfy the law of conservation of mass. Q3. Name the reactants in Zn + H₂SO₄ → ZnSO₄ + H₂ Ans. Zn and H₂SO₄. Q4. Which gas is evolved when zinc reacts with dilute acid? Ans. Hydrogen gas. Q5. What is corrosion? Ans. Slow destruction of a metal by chemical reaction with air and moisture. Q6. Give one example of oxidation. Ans. 2Mg + O₂ → 2MgO. Q7. Give one example of reduction. Ans. CuO + H₂ → Cu + H₂O. Q8. What is a skeletal equation? Ans. An unbalanced chemical equation. Q9. What is rancidity? Ans. Oxidation of oils and fats causing bad smell and taste. Q10. Which substance is reduced in CuO + H₂ → Cu + H₂O ? Ans. Copper(II) oxide (CuO). --- 2. Short answer questions (2–3 marks)...