NCERT based MCQ of Class 10th, Chapter-2, Acids, Bases and Salts with brief explanation for competitive exams like TGT HTET, KVS PGT, TGT NVS, TGT EMRS, SSC and all other state competition exams.
Along with MCQ, Chapter Key-Points for quick learning NCERT related facts are also discussed below.
Right Answer for MCQ will be highlighted on Hover / Click on the option.
Summary of the Chapter-2-Acids, Bases and Salts with Key-Points:
- Acid-base indicators are substances, often dyes or dye mixtures, that help identify the presence of acids and bases.
- A substance's acidic nature is due to the generation of H⁺ (aq) ions in a solution, while the basic nature arises from the production of OH⁻ (aq) ions.
- When acids react with metals, hydrogen gas is released, and a corresponding salt is produced.
- When bases react with metals, hydrogen gas is also released, and the resulting salt contains negative ions made up of metal and oxygen.
- The reaction between acids and metal carbonates or metal bicarbonates results in the formation of a salt, carbon dioxide gas, and water.
- Acidic and basic solutions in water can conduct electricity due to the production of hydrogen and hydroxide ions, respectively.
- The pH scale, ranging from 0 to 14, measures the hydrogen ion concentration in a solution, indicating the strength of acids or alkalis.
- A neutral solution has a pH of 7, while an acidic solution has a pH below 7, and a basic solution has a pH above 7.
- Metabolic activities in living organisms occur within a specific pH range.
- Mixing concentrated acids or bases with water releases a large amount of heat, making it a highly exothermic process.
- Acids and bases neutralize each other to produce corresponding salts and water.
- Water of crystallization refers to the fixed number of water molecules contained within one formula unit of a salt.
- Salts are widely used in daily life and various industrial processes.
1. Which of the following substances would you suggest as a remedy for acidity caused by overeating?
(A) Lemon juice
(B) Vinegar
(C) Baking soda solution
(D) Milk
Explanation: Baking soda (sodium bicarbonate) is a base that neutralizes excess stomach acid, providing relief from acidity. Lemon juice and vinegar are acids and would worsen the condition.
2. What change in color does blue litmus paper show when it comes in contact with an acidic solution?
(A) No change
(B) Turns red
(C) Turns blue
(D) Turns green
Explanation: Acids turn blue litmus paper red. This property is used to identify acidic solutions.
3. Which of the following indicators can be used to identify acids and bases based on their odor change?
(A) Methyl orange
(B) Phenolphthalein
(C) Turmeric
(D) Onion
Explanation: Onion is an olfactory indicator, which means it changes odor when exposed to acidic or basic environments, unlike other indicators like methyl orange and phenolphthalein which change color.
4. Which gas is evolved when acids react with metals like zinc?
(A) Carbon dioxide
(B) Oxygen
(C) Nitrogen
(D) Hydrogen
Explanation: Acids react with metals to form a salt and release hydrogen gas, which can be tested by bringing a burning splint close to the gas; it will pop.
5. What is formed when a metal carbonate reacts with an acid?
(A) Salt, carbon dioxide, and water
(B) Salt and hydrogen gas
(C) Only salt
(D) Water and carbon monoxide
Explanation: Metal carbonates react with acids to produce salt, carbon dioxide, and water, often observed as effervescence.
6. Which of the following is a neutralization reaction?
(A) Acid + Metal → Salt + Hydrogen gas
(B) Acid + Base → Salt + Water
(C) Base + Metal → Salt + Water
(D) Acid + Metal carbonate → Salt + Carbon dioxide + Water
Explanation: A neutralization reaction occurs when an acid and a base react to form salt and water, balancing each other's properties.
7. Which ion is responsible for the basic nature of a substance?
(A) H+
(B) OH–
(C) Cl–
(D) Na+
Explanation: The hydroxide ion (OH–) is responsible for the basic properties of a substance, increasing its pH.
8. Which of the following has a pH value of less than 7?
(A) Distilled water
(B) Baking soda solution
(C) Lemon juice
(D) Sodium hydroxide
Explanation: Lemon juice is acidic with a pH below 7, indicating the presence of citric acid.
9. Why is it recommended to add acid to water rather than water to acid?
(A) To prevent a temperature decrease
(B) To avoid a violent exothermic reaction
(C) To ensure complete mixing
(D) To dilute the acid properly
Explanation: Adding water to a concentrated acid can cause the acid to splash due to the heat generated, potentially causing burns or breaking the container.
10. Which compound is commonly used in baking and as an antacid?
(A) Sodium chloride
(B) Sodium hydrogen carbonate
(C) Calcium carbonate
(D) Magnesium hydroxide
Explanation: Sodium hydrogen carbonate (baking soda) is used in cooking to make baked goods rise and as an antacid to neutralize excess stomach acid.
11. What happens when you add phenolphthalein to a basic solution?
(A) The solution turns pink
(B) The solution turns red
(C) The solution remains colorless
(D) The solution turns blue
Explanation: Phenolphthalein is a colorless indicator in acidic solutions but turns pink in basic solutions, indicating the presence of a base.
12. Which of the following reactions demonstrates a base reacting with a non-metallic oxide?
(A) NaOH + HCl → NaCl + H₂O
(B) Ca(OH)₂ + CO₂ → CaCO₃ + H₂O
(C) Zn + H₂SO₄ → ZnSO₄ + H₂
(D) NaOH + Zn → Na₂ZnO₂ + H₂
Explanation: This reaction shows a base (calcium hydroxide) reacting with a non-metallic oxide (carbon dioxide) to form a salt (calcium carbonate) and water, indicating that non-metallic oxides are acidic.
13. What is the main component responsible for the basic nature of soaps?
(A) Potassium hydroxide
(B) Sodium hydroxide
(C) Calcium hydroxide
(D) Magnesium hydroxide
Explanation: Sodium hydroxide is commonly used in soap making; it is a strong base, making soaps alkaline.
14. What pH range is required for most aquatic life to survive in rivers?
(A) 0 to 3
(B) 5 to 6
(C) 7 to 8
(D) 10 to 12
Explanation: Most aquatic life survives in a neutral to slightly basic pH range (7-8). Acidic conditions (below pH 7) can be harmful to aquatic organisms.
15. Which acid is found in vinegar?
(A) Citric acid
(B) Acetic acid
(C) Lactic acid
(D) Oxalic acid
Explanation: Acetic acid is the main component of vinegar, giving it a sour taste.
16. What color change is observed when turmeric is exposed to a basic solution?
(A) Turns red
(B) Turns yellow
(C) Turns blue
(D) Turns green
Explanation: Turmeric turns reddish-brown when exposed to basic solutions, making it an indicator of bases.
17. Which of the following substances is used to test for carbon dioxide gas?
(A) Limewater
(B) Blue litmus paper
(C) Phenolphthalein
(D) Methyl orange
Explanation: Limewater turns milky when carbon dioxide gas is passed through it due to the formation of calcium carbonate.
18. Which gas is produced when acids react with metal carbonates?
(A) Hydrogen
(B) Oxygen
(C) Carbon dioxide
(D) Nitrogen
Explanation: Acids react with metal carbonates to release carbon dioxide gas, which is responsible for the fizzing observed.
19. Which of the following compounds will neutralize an acid spill in a laboratory?
(A) Sodium chloride
(B) Calcium hydroxide
(C) Hydrochloric acid
(D) Sulfuric acid
Explanation: Calcium hydroxide is a base that can neutralize acids by reacting with them to form water and salt, thus neutralizing the spill.
20. What is the main reason acids conduct electricity in aqueous solutions?
(A) Presence of free electrons
(B) Presence of metal ions
(C) Formation of hydrogen ions
(D) Formation of oxygen molecules
Explanation: Acids ionize in water to produce hydrogen ions, which carry the electric current, making the solution conductive.