Previous Year Questions: Chemical Reactions & Equations

Previous Year Questions: Chemical Reactions & Equations Previous Year Questions: Chemical Reactions & Equations Previous Year Questions 2025 Q1: Electrolysis of water is a decomposition reaction. The mass ratio (MH : MO) of hydrogen and oxygen gases liberated at the electrodes during electrolysis of water is: (a) 8:1 (b) 2:1 (c) 1:2 (d) 1:8 Ans: (d) 1:8. During the electrolysis of water, water decomposes to form hydrogen and oxygen gases. The volume ratio of hydrogen to oxygen is 2 : 1 , but since oxygen is eight times heavier than hydrogen, the mass ratio (Mₕ : Mₒ) is 1 : 8 . Q2: Consider the following reactions: (i) Dilute hydrochloric acid reacts with sodium hydroxide (ii) Magnesium oxide reacts with dilute hydrochloric acid (iii) Carbon dioxide reacts with sodium hydroxide. It is found that in each case: (a) Salt and water is formed (b) Neutral salts are formed (c) Hydrogen gas is formed (d) Acidic salts are formed Ans: (a) Salt and water is formed. In all three reactions, an acid…