Acids, Bases and Salts
- How is the concentration of hydroxide ions (OH−) affected when excess base is dissolved The concentration of hydroxide ions (OH⁻) would increase when excess base is dissolved in a solution of sodium hydroxide. 1
- How is the concentration of hydronium ions (H3O+) affected when a solution of an acid is diluted? When an acid is diluted, the concentration of hydronium ions (H₃O⁺) per unit volume decreases. This means that the strength of the acid decr... 1
- While diluting an acid, why is it recommended that the acid should be added to water Since the process of dissolving an acid in water is exothermic, it is always recommended that acid should be added to water. If it is done t... 1
- Why does dry HCl gas not change the colour of the dry litmus paper? Dry HCl gas not change the colour of the dry litmus paper because it has no Hydrogen ions (H⁺) in it. 1
- Why does an aqueous solution of an acid conduct electricity? The presence of hydrogen (H⁺) or hydronium (H₃O⁺) ions in the aqueous solution of an acid are responsible for conducting electricity. 1
- Why do HCl, HNO3, etc., show acidic characters in aqueous solutions while solutions of compounds When HCl or HNO₃ are mixed with water then they dissolve in water to form H⁺ or H₃O⁺ ions which shows their acidic character. For example ju... 1
- Metal compound A reacts with dilute hydrochloric acid to produce effervescence. CaCO₃ (s) + 2HCl (aq) → CaCl₂ (aq) + CO₂ (g) + H₂O (l) Calcium Carbonate + Hydrochloric acid → Calcium Chloride + Carbon dioxide + Water 1
- Which gas is usually liberated when an acid reacts with a metal? Hydrogen gas is usually liberated when an acid reacts with a metal For example: When zinc granules react with dilute sulphuric acid, then hy... 1
- Why should curd and sour substances not be kept in brass and copper vessels? Curd and other sour substances contain acids. Therefore, when they are kept in brass and copper vessels, the metal reacts with the acid to l... 2
- You have been provided with three test tubes. One of them contains distilled water Answer: Use red litmus to find the base first, then use the blue litmus obtained from it to find the acid; the remaining tube is distilled w... 1