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Acids, Bases and Salts — Class 10 CBSE Science MCQs with Solutions
Free Class 10 CBSE Science Acids, Bases and Salts MCQs with step-by-step solutions. Practise online on Prepizo — no login needed.
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Sample questions with solutions
Q1 — easy
Which gas is liberated when an acid reacts with an active metal?
A. Oxygen
B. Hydrogen ✓ Correct
C. Carbon dioxide
D. Nitrogen
Solution: Acid + Metal → Salt + Hydrogen gas.
Q2 — easy
When marble/eggshells (calcium carbonate) react with dilute HCl, the gas evolved turns lime water milky. The gas is:
A. Hydrogen
B. Carbon dioxide (CO₂) ✓ Correct
C. Oxygen
D. Nitrogen
Solution: Carbonates react with acids to liberate CO₂ gas.
Q3 — easy
pH of a neutral aqueous solution at 25°C is:
A. 0
B. 7 ✓ Correct
C. 14
D. 1
Solution: A neutral solution has pH = 7.
Q4 — easy
Strong acids have pH values ranging between:
A. 0 to 3 ✓ Correct
B. 7 to 9
C. 12 to 14
D. 6 to 7
Solution: Lower pH values (0-3) represent high H⁺ concentration / strong acidity.
Q5 — easy
Tooth decay starts when the pH of mouth falls below:
A. 7.0
B. 6.5
C. 5.5 ✓ Correct
D. 8.0
Solution: Enamel corrodes when bacterial acid lowers mouth pH below 5.5.
Q6 — easy
Chemical name of Bleaching Powder used as a disinfectant is:
A. Calcium carbonate
B. Calcium oxychloride (CaOCl₂) ✓ Correct
C. Calcium hydroxide
D. Sodium hydrogen carbonate
Solution: Bleaching powder is Calcium Oxychloride (CaOCl₂).
Q7 — easy
Baking soda, used in baking cakes and antacids, is chemically:
A. Sodium carbonate (Na₂CO₃)
B. Sodium hydrogen carbonate (NaHCO₃) ✓ Correct
C. Calcium sulphate
D. Sodium hydroxide
Solution: Baking soda is Sodium Hydrogen Carbonate / Bicarbonate (NaHCO₃).
Q8 — easy
Washing soda crystals contain how many molecules of water of crystallization?
A. 2
B. 5
C. 10 (Na₂CO₃·10H₂O) ✓ Correct
D. 7
Solution: Washing soda is Sodium Carbonate Decahydrate (Na₂CO₃·10H₂O).
Q9 — easy
Plaster of Paris (CaSO₄·½H₂O) sets into a hard solid mass called Gypsum on mixing with water. Formula of Gypsum is:
A. CaSO₄·2H₂O ✓ Correct
B. CaSO₄·5H₂O
C. CaSO₄·10H₂O
D. 2CaSO₄·H₂O
Solution: Gypsum is Calcium Sulphate Dihydrate (CaSO₄·2H₂O).
Q10 — easy
Sting of honeybee/ant contains formic acid. Relief can be obtained by applying mild basic substance:
A. Lemon juice
B. Vinegar
C. Baking soda paste ✓ Correct
D. Dilute HCl
Solution: Baking soda (NaHCO₃) neutralizes the acidic sting.
Q11 — easy
Sting of nettle plant leaves injects methanoic acid. Natural herbal remedy found nearby is leaves of:
A. Neem plant
B. Dock plant ✓ Correct
C. Tulsi plant
D. Mint plant
Solution: Dock plant leaves provide a basic juice that neutralizes nettle stings.
Q12 — easy
Acid present in tamarind and unripe grapes is:
A. Citric acid
B. Tartaric acid ✓ Correct
C. Oxalic acid
D. Lactic acid
Solution: Tamarind contains tartaric acid.
Q13 — easy
Acid present in tomatoes is:
A. Acetic acid
B. Oxalic acid ✓ Correct
C. Lactic acid
D. Citric acid
Solution: Tomatoes contain oxalic acid.
Q14 — easy
Chlor-alkali process of electrolyzing brine (aqueous NaCl) produces:
A. NaOH, Cl₂, and H₂ ✓ Correct
B. Na, Cl₂, and O₂
C. NaHCO₃ and HCl
D. CaOCl₂ and H₂O
Solution: 2NaCl + 2H₂O → 2NaOH + Cl₂ + H₂.
Q15 — easy
Which salt is used in fire extinguishers and baking powders?
A. Na₂CO₃
B. NaHCO₃ ✓ Correct
C. CuSO₄
D. NaCl
Solution: NaHCO₃ decomposes upon heating to release fire-extinguishing CO₂ gas.