ACIDS, BASES AND SALTS
PRACTICE QUESTIONS FOR TET/CTET/TRT/GROUPS/UPSC/NEET/JL
1-20 QUESTIONS
1. Acids taste –
a) Sweet
b) Bitter
c) Sour ✅
d) Salty
Explanation: Acids such as lemon juice and vinegar have a sour taste due to the presence of hydrogen ions (H⁺).
2. Bases taste –
a) Sweet
b) Bitter ✅
c) Sour
d) Salty
Explanation: Bases like baking soda and soap taste bitter and feel soapy due to hydroxide ions (OH⁻).
3. Substances that change color to indicate acidic or basic nature are called –
a) Catalysts
b) Indicators ✅
c) Reactants
d) Solvents
Explanation: Indicators such as litmus and phenolphthalein change color based on pH.
4. Litmus turns red in –
a) Acid ✅
b) Base
c) Neutral solution
d) Water
Explanation: Blue litmus paper turns red in acidic solutions due to high H⁺ ion concentration.
5. Litmus turns blue in –
a) Acid
b) Base ✅
c) Neutral
d) Alcohol
Explanation: Red litmus paper becomes blue in a base because bases contain OH⁻ ions.
6. Which of the following is a natural indicator?
a) Methyl orange
b) Turmeric ✅
c) Phenolphthalein
d) Methanol
Explanation: Turmeric changes color from yellow to red-brown in bases.
7. The acid present in lemon juice is –
a) Hydrochloric acid
b) Citric acid ✅
c) Nitric acid
d) Acetic acid
Explanation: Lemon contains citric acid, which gives it a sour taste.
8. The acid in vinegar is –
a) Citric
b) Formic
c) Acetic ✅
d) Lactic
Explanation: Vinegar is a dilute solution of acetic acid (CH₃COOH).
9. The acid in milk is –
a) Acetic acid
b) Lactic acid ✅
c) Citric acid
d) Sulphuric acid
Explanation: During curdling, lactose converts into lactic acid by bacteria.
10. The acid injected by ants is –
a) Formic acid ✅
b) Acetic acid
c) Citric acid
d) Hydrochloric acid
Explanation: Formic acid (methanoic acid) causes the sting of ant bites.
11. The main acid in the human stomach is –
a) Nitric acid
b) Hydrochloric acid ✅
c) Sulphuric acid
d) Acetic acid
Explanation: HCl helps digestion and kills germs in the stomach.
12. Bases are –
a) Sour
b) Sweet
c) Bitter and soapy ✅
d) Odorless
Explanation: Bases like NaOH and KOH are bitter and slippery to touch.
13. The base found in lime water is –
a) Sodium hydroxide
b) Calcium hydroxide ✅
c) Magnesium hydroxide
d) Potassium hydroxide
Explanation: Lime water = Ca(OH)₂ (a weak base).
14. Sodium hydroxide is commonly known as –
a) Baking soda
b) Caustic soda ✅
c) Washing soda
d) Bleaching powder
Explanation: NaOH is called caustic soda, a strong base.
15. Potassium hydroxide is called –
a) Caustic potash ✅
b) Washing soda
c) Baking soda
d) Caustic lime
Explanation: KOH is caustic potash, a strong base used in soaps.
16. Which indicator turns pink in a base?
a) Methyl orange
b) Phenolphthalein ✅
c) Turmeric
d) Litmus
Explanation: Phenolphthalein becomes pink in basic solutions.
17. Methyl orange turns red in –
a) Acid ✅
b) Base
c) Water
d) Alcohol
Explanation: Acidic solution changes methyl orange to red; basic turns it yellow.
18. Ammonium hydroxide (NH₄OH) is a –
a) Strong acid
b) Weak base ✅
c) Strong base
d) Neutral
Explanation: NH₄OH is a weak base found in window cleaners.
19. Common salt is chemically known as –
a) NaCl ✅
b) KCl
c) NaOH
d) Na₂CO₃
Explanation: Sodium chloride is the chemical name of common salt.
20. Neutralization reaction involves –
a) Acid + Acid
b) Acid + Base ✅
c) Base + Salt
d) Acid + Water
Explanation: Acid and base react to form salt and water (neutralization).
21-40 QUESTIONS
21. The products of neutralization are –
a) Salt and water ✅
b) Hydrogen and oxygen
c) Acid and base
d) Carbon dioxide
Explanation: Example: HCl + NaOH → NaCl + H₂O.
22. Which reaction produces salt and water?
a) Neutralization ✅
b) Displacement
c) Decomposition
d) Oxidation
Explanation: Acid-base reactions yield salt and water.
23. The pH value of a neutral solution is –
a) 0
b) 7 ✅
c) 14
d) 5
Explanation: Pure water has pH 7 (neutral).
24. The pH value less than 7 indicates –
a) Acidic nature ✅
b) Basic
c) Neutral
d) Strong base
Explanation: Lower pH means higher H⁺ ion concentration.
25. The pH value greater than 7 indicates –
a) Acidic
b) Basic ✅
c) Neutral
d) Weak acid
Explanation: Higher pH = more OH⁻ ions (basic).
26. pH scale ranges from –
a) 0–7
b) 0–10
c) 0–14 ✅
d) 1–14
Explanation: The pH scale runs from 0 (strong acid) to 14 (strong base).
27. Acid rain has a pH –
a) 5.6 ✅
b) 7
c) 9
d) 10
Explanation: Rainwater with pH below 5.6 is considered acid rain.
28. pH of human blood is –
a) 6.0
b) 7.4 ✅
c) 8.0
d) 9.0
Explanation: Blood is slightly basic to maintain body balance.
29. Substance used to neutralize acidity in soil –
a) Lime ✅
b) Acid
c) Gypsum
d) Vinegar
Explanation: Lime (CaO) neutralizes acidic soil.
30. pH of milk is about –
a) 4.5 to 6.5 ✅
b) 7.5
c) 8.5
d) 10
Explanation: Slightly acidic due to lactic acid content.
31. The chemical formula of bleaching powder is –
a) CaCO₃
b) CaOCl₂ ✅
c) CaCl₂
d) CaSO₄
Explanation: Bleaching powder = calcium oxychloride (CaOCl₂).
32. Bleaching powder is prepared from –
a) Slaked lime and chlorine gas ✅
b) Soda and HCl
c) CaCO₃ and SO₂
d) NaCl and H₂SO₄
Explanation: Ca(OH)₂ + Cl₂ → CaOCl₂ + H₂O.
33. Plaster of Paris is chemically –
a) CaSO₄·½H₂O ✅
b) CaCO₃
c) CaOCl₂
d) CaSO₄·2H₂O
Explanation: Gypsum when heated forms CaSO₄·½H₂O.
34. Gypsum formula –
a) CaSO₄·2H₂O ✅
b) CaSO₄
c) CaCO₃
d) Ca(OH)₂
Explanation: Gypsum is calcium sulphate dihydrate.
35. Baking soda formula –
a) Na₂CO₃
b) NaHCO₃ ✅
c) NaOH
d) Na₂SO₄
Explanation: Baking soda = sodium bicarbonate (NaHCO₃).
36. Washing soda formula –
a) Na₂CO₃·10H₂O ✅
b) NaHCO₃
c) NaOH
d) Na₂SO₄
Explanation: Washing soda is sodium carbonate decahydrate.
37. Which gas turns lime water milky?
a) Oxygen
b) Carbon dioxide ✅
c) Hydrogen
d) Nitrogen
Explanation: CO₂ + Ca(OH)₂ → CaCO₃ (white precipitate).
38. The pH paper shows color –
a) Same for all solutions
b) Varies with solution ✅
c) Always red
d) Always blue
Explanation: Each pH value corresponds to a different color on pH paper.
39. Tooth decay is caused by –
a) Strong base
b) Acidic nature ✅
c) Alkaline water
d) Salts
Explanation: Acids formed by bacteria lower pH and damage enamel.
40. Acid used in car batteries –
a) Sulphuric acid ✅
b) Nitric acid
c) Hydrochloric acid
d) Carbonic acid
Explanation: Lead-acid batteries use H₂SO₄.
41 – 60 QUESTIONS
41. Acid used in fertilizers –
a) Phosphoric acid ✅
b) Citric acid
c) Hydrochloric acid
d) Acetic acid
Explanation: H₃PO₄ is essential for phosphate fertilizers.
42. The base used in antacids –
a) Mg(OH)₂ ✅
b) NaOH
c) KOH
d) CaO
Explanation: Milk of magnesia neutralizes excess stomach acid.
43. The neutral salt formed by strong acid and strong base is –
a) NaCl ✅
b) Na₂CO₃
c) CH₃COONa
d) NH₄Cl
Explanation: HCl + NaOH → NaCl + H₂O produces neutral salt.
44. Acid used for cleaning metals –
a) H₂SO₄
b) HCl ✅
c) HNO₃
d) HCOOH
Explanation: Hydrochloric acid removes rust and stains from metal surfaces.
45. Substance used in the manufacture of glass and soap –
a) Sodium carbonate ✅
b) Calcium carbonate
c) Sodium chloride
d) Baking soda
Explanation: Na₂CO₃ is used in detergents and glassmaking.
46. The common name of Na₂CO₃ is –
a) Washing soda ✅
b) Baking soda
c) Common salt
d) Slaked lime
Explanation: Na₂CO₃·10H₂O is washing soda.
47. Acid that forms when carbon dioxide dissolves in water –
a) Carbonic acid ✅
b) Nitric acid
c) Sulphuric acid
d) Acetic acid
Explanation: CO₂ + H₂O → H₂CO₃.
48. A base reacts with non-metallic oxide to form –
a) Salt and water ✅
b) Hydrogen
c) Oxygen
d) Acid
Explanation: Non-metallic oxides act as acids (acidic oxides).
49. The pH of gastric juice is –
a) 1.2 to 3 ✅
b) 5
c) 7
d) 10
Explanation: Stomach acid (HCl) makes gastric juice highly acidic.
50. The colour of phenolphthalein in acid is –
a) Pink
b) Colourless ✅
c) Red
d) Yellow
Explanation: Phenolphthalein is colorless in acids and pink in bases.
51. Acid used in explosives –
a) Nitric acid ✅
b) Acetic acid
c) Hydrochloric acid
d) Sulphurous acid
Explanation: HNO₃ is used in making TNT and dynamite.
52. Which salt gives blue crystals?
a) CuSO₄·5H₂O ✅
b) Na₂CO₃·10H₂O
c) NaCl
d) CaSO₄
Explanation: Copper sulphate crystals are blue due to water of crystallization.
53. Which salt loses water on heating and turns white?
a) CuSO₄·5H₂O ✅
b) NaCl
c) NaOH
d) NaHCO₃
Explanation: On heating, hydrated CuSO₄ loses water and turns white.
54. Water of crystallization means –
a) Fixed number of water molecules ✅
b) Free water
c) Bound water
d) Any moisture
Explanation: It’s the definite water content in hydrated salts.
55. Acidic oxides are generally –
a) Metal oxides
b) Non-metal oxides ✅
c) Salts
d) Bases
Explanation: Non-metals like CO₂, SO₂ form acidic oxides.
56. Basic oxides are –
a) Metal oxides ✅
b) Non-metal oxides
c) Salts
d) Acids
Explanation: Metal oxides like Na₂O, CaO react with acids to form salts.
57. Substance used to make plaster casts in hospitals –
a) Plaster of Paris ✅
b) Bleaching powder
c) Lime
d) Cement
Explanation: POP hardens quickly and supports fractured bones.
58. The strongest acid among the following is –
a) H₂SO₄ ✅
b) H₂CO₃
c) CH₃COOH
d) H₃PO₄
Explanation: Sulphuric acid is a strong diprotic acid.
59. Substance used in removing permanent hardness of water –
a) Washing soda ✅
b) Baking soda
c) Vinegar
d) Bleaching powder
Explanation: Na₂CO₃ removes Ca²⁺ and Mg²⁺ ions from hard water.
60. When acid reacts with a metal, it produces –
a) Hydrogen gas ✅
b) Oxygen
c) Nitrogen
d) CO₂
Explanation: Example: Zn + H₂SO₄ → ZnSO₄ + H₂↑.
61 – 80 QUESTIONS
61. Which of the following is an amphoteric oxide?
a) CO₂ b) Na₂O
c) Al₂O₃ ✅ d) CaO
Explanation: Amphoteric oxides show both acidic and basic behaviour; aluminium oxide reacts with acids & bases.
62. When a base reacts with an acid, heat is —
a) Absorbed b) Evolved ✅
c) Constant d) None
Explanation: Neutralization reactions are exothermic; they release heat.
63. Which of these is not an indicator?
a) Litmus b) Sugar ✅
c) Methyl orange d) Turmeric
Explanation: Sugar does not change colour with acids/bases.
64. The reaction between NaOH and HCl is —
a) Neutralization ✅ b) Redox
c) Substitution d) Oxidation
Explanation: Acid + Base → Salt + Water (NaCl + H₂O).
65. Substances with pH < 7 are —
a) Basic b) Acidic ✅
c) Neutral d) Salts
Explanation: Acids have a hydrogen-ion concentration higher than OH⁻ ions.
66. pH = 7 means the solution is —
a) Acidic b) Basic
c) Neutral ✅ d) None
Explanation: Pure water at 25 °C has equal H⁺ and OH⁻ ions.
67. Which of the following shows pH > 7?
a) Lemon juice b) Vinegar
c) Baking-soda solution ✅ d) Tomato juice
Explanation: Baking soda is basic (contains NaHCO₃).
68. Which acid is used in the manufacture of fertilizers and paints?
a) Acetic b) Sulphuric acid ✅
c) Citric d) Hydrochloric
Explanation: H₂SO₄ is known as the “King of Chemicals” used in many industries.
69. Which gas is evolved when zinc reacts with H₂SO₄?
a) Oxygen b) Hydrogen ✅
c) Carbon dioxide d) Nitrogen
Explanation: Zn + H₂SO₄ → ZnSO₄ + H₂↑.
70. Acid used in soft drinks —
a) Hydrochloric b) Carbonic acid ✅
c) Sulphuric d) Citric
Explanation: CO₂ + H₂O → H₂CO₃ gives tangy taste in aerated drinks.
71. When H₂SO₄ reacts with NaOH, the salt formed is —
a) Na₂SO₄ ✅ b) NaCl
c) Na₂CO₃ d) NaHCO₃
Explanation: H₂SO₄ + 2 NaOH → Na₂SO₄ + 2 H₂O.
72. Neutralization reactions are —
a) Endothermic b) Exothermic ✅
c) Photochemical d) Oxidation
Explanation: They release heat and sometimes steam.
73. Which of the following pairs forms a neutral solution?
a) HCl + NaOH ✅ b) HCl + NH₄OH
c) H₂SO₄ + NH₄OH d) CH₃COOH + NaOH
Explanation: Strong acid + strong base → neutral pH 7.
74. Which acid is present in tomatoes?
a) Oxalic acid ✅ b) Tartaric c) Citric d) Lactic
Explanation: Gives tomatoes their sour flavour.
75. Chemical formula of gypsum —
a) CaSO₄·2H₂O ✅ b) CaSO₄·½H₂O
c) CaCO₃ d) CaO
Explanation: Calcium sulphate dihydrate.
76. When POP reacts with water it forms —
a) Salt b) Gypsum ✅
c) Lime d) Chalk
Explanation: CaSO₄·½H₂O + 1½H₂O → CaSO₄·2H₂O.
77. Substance used in white-washing walls —
a) Slaked lime ✅ b) POP
c) Soda ash d) Lime stone
Explanation: Ca(OH)₂ reacts with CO₂ forming CaCO₃ on walls.
78. The colour of copper sulphate crystals is —
a) White b) Blue ✅
c) Green d) Pink
Explanation: CuSO₄·5H₂O gives a characteristic blue colour.
79. On heating blue copper sulphate, it becomes —
a) White ✅ b) Green
c) Yellow d) Pink
Explanation: Water of crystallization removed → anhydrous CuSO₄.
80. Base used in the manufacturing of soap —
a) H₂SO₄ b) NaOH ✅
c) HCl d) CaO
Explanation: Caustic soda reacts with fats to produce soap.
81 – 100 QUESTIONS
81. Strong base among the following —
a) NH₄OH b) Ca(OH)₂
c) NaOH ✅ d) Mg(OH)₂
Explanation: NaOH completely ionizes in water.
82. Weak acid among the following —
a) HCl b) H₂SO₄
c) CH₃COOH ✅ d) HNO₃
Explanation: Acetic acid only partially ionizes.
83. The base used in toothpaste to neutralize acid is —
a) Calcium carbonate ✅ b) Sodium chloride
c) Sodium carbonate d) CaO
Explanation: Neutralizes acids produced by mouth bacteria.
84. Acid used in pickles —
a) Citric b) Acetic acid ✅
c) Formic d) Sulphuric
Explanation: Vinegar (acetic acid) preserves food by killing microbes.
85. The chemical used in fire extinguishers —
a) CO₂ ✅ b) N₂
c) O₂ d) SO₂
Explanation: CO₂ cuts off the oxygen supply and cools flames.
86. Salt used in baking powders —
a) Na₂CO₃ b) NaHCO₃ ✅
c) NaCl d) K₂CO₃
Explanation: Baking soda releases CO₂ on heating, making cakes soft.
87. Salt obtained by combining weak acid and strong base —
a) Sodium acetate ✅ b) NaCl
c) NH₄Cl d) KNO₃
Explanation: CH₃COOH + NaOH → CH₃COONa + H₂O.
88. Water of crystallization of washing soda —
a) 2 molecules b) 5 molecules
c) 10 molecules ✅ d) 7 molecules
Explanation: Na₂CO₃·10H₂O.
89. Acid used for etching glass —
a) Hydrofluoric acid ✅ b) Hydrochloric
c) Nitric d) Acetic
Explanation: HF reacts with SiO₂ to etch the glass surface.
90. Substance that neutralizes bee-sting acidity —
a) Vinegar b) Baking soda ✅
c) Soap d) Lemon juice
Explanation: Bee sting = formic acid; NaHCO₃ (base) neutralizes it.
91. The acid in soft drinks gives a fizz due to —
a) O₂ b) CO₂ ✅
c) H₂ d) N₂
Explanation: CO₂ gas under pressure forms carbonic acid.
92. Milk of magnesia contains —
a) Ca(OH)₂ b) Mg(OH)₂ ✅
c) NaOH d) KOH
Explanation: Mild base used as an antacid.
93. The neutralization reaction used in daily life —
a) Antacid tablets ✅ b) Photosynthesis
c) Combustion d) Rusting
Explanation: Antacids neutralize excess HCl in the stomach.
94. Acidic soil is treated with —
a) Vinegar b) Quick lime ✅
c) Sulphuric acid d) Sodium chloride
Explanation: Lime (CaO) raises soil pH to neutral.
95. The gas evolved when the acid reacts with the marble chips —
a) Hydrogen b) Carbon dioxide ✅
c) Oxygen d) Nitrogen
Explanation: CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂.
96. Which one is not a base?
a) NaOH b) KOH
c) Ca(OH)₂ d) H₂SO₄ ✅
Explanation: H₂SO₄ is a strong acid, not a base.
97. Blue vitriol is —
a) Na₂CO₃ b) CuSO₄·5H₂O ✅
c) FeSO₄ d) MgSO₄
Explanation: Blue crystals of hydrated copper sulphate.
98. Green vitriol is —
a) FeSO₄·7H₂O ✅ b) CuSO₄·5H₂O
c) MgSO₄ d) Na₂SO₄
Explanation: Hydrated ferrous sulphate appears green.
99. White vitriol is —
a) FeSO₄ b) CuSO₄
c) ZnSO₄·7H₂O ✅ d) Na₂SO₄
Explanation: Hydrated zinc sulphate is called white vitriol.
100. The chemical used for making bleaching powder —
a) HCl b) Cl₂ ✅
c) SO₂ d) O₂
Explanation: Cl₂ reacts with Ca(OH)₂ to form CaOCl₂.
101 – 120 QUESTIONS
101. Which of the following is a weak base?
a) NaOH b) KOH
) NH₄OH ✅ d) Ca(OH)₂
Explanation: Ammonium hydroxide partially ionizes in water.
102. Neutral salts show pH ≈ 7 because —
a) They are dry b) They are formed by strong acid & base ✅
c) They evaporate d) They oxidize
Explanation: NaCl is neutral since HCl & NaOH are strong.
103. Which of the following is an acidic salt?
a) Na₂CO₃ b) NaHSO₄ ✅
c) NaCl d) CH₃COONa
Explanation: Formed by the partial neutralization of a strong acid with a base.
104. Basic salt example —
a) Na₂CO₃ ✅ b) NaCl
c) KNO₃ d) CuSO₄
Explanation: Formed by a strong base & a weak acid.
105. Which one is used for softening of hard water?
a) Baking soda b) Washing soda ✅
c) Vinegar d) Lime
Explanation: Na₂CO₃ precipitates Ca²⁺ and Mg²⁺ ions.
106. A base used in the textile industry —
a) HCl b) NaOH ✅
c) NaCl d) Na₂CO₃
Explanation: Caustic soda helps in scouring and bleaching fabrics.
107. Acid used in the preparation of POP —
a) Sulphuric acid ✅ b) Nitric
c) Hydrochloric d) Carbonic
Explanation: Gypsum treated with H₂SO₄ forms CaSO₄·½H₂O.
108. The base present in window cleaners —
a) NaOH b) NH₄OH ✅
c) KOH d) Ca(OH)₂
Explanation: Ammonium hydroxide removes grease and stains.
109. Acid present in curd —
a) Citric b) Lactic acid ✅
c) Formic d) Sulphuric
Explanation: Produced by fermentation of lactose by bacteria.
110. Which acid is known as ‘aqua fortis’?
a) Nitric acid ✅ b) Hydrochloric
c) Sulphuric d) Acetic
Explanation: Latin name ‘aqua fortis’ means strong water for HNO₃.
111. pH of soap solution is —
a) 6 b) 7
c) > 7 ✅ d) < 7
Explanation: Soap solution is basic in nature.
112. Acid used in the preservation of pickles and sauce —
a) Acetic acid ✅ b) Formic
c) Hydrochloric d) Sulphuric
Explanation: Vinegar acts as a natural preservative.
113. Salt of a weak base and a strong acid —
a) NaCl b) Na₂CO₃
c) NH₄Cl ✅ d) KNO₃
Explanation: NH₄Cl = weak base (NH₄OH) + strong acid (HCl); acidic salt.
114. Colour of litmus in neutral solution —
a) Purple ✅ b) Red c) Blue d) Yellow
Explanation: Neutral pH gives violet/purple colour.
115. Lime water turns milky due to —
a) O₂ b) CO₂ ✅
c) N₂ d) H₂
Explanation: Ca(OH)₂ + CO₂ → CaCO₃ (white precipitate).
116. Strongest base among the following —
a) Mg(OH)₂ b) Ca(OH)₂
c) NaOH ✅ d) NH₄OH
Explanation: NaOH completely dissociates, producing max OH⁻.
117. Acidic oxide among the following —
a) Na₂O b) CO₂ ✅
c) CaO d) MgO
Explanation: Non-metal oxide CO₂ forms an acid on reaction with water.
118. Base used in the manufacturing of bleaching powder —
a) NaOH b) Ca(OH)₂ ✅
c) KOH d) Mg(OH)₂
Explanation: Slaked lime reacts with Cl₂ gas to form CaOCl₂.
119. The industrial process of manufacturing NaOH is —
a) Chlor-alkali process ✅ b) Contact process
c) Haber process d) Solvay process
Explanation: Electrolysis of brine produces NaOH, Cl₂, and H₂.
120. The process used for the preparation of washing soda from brine is —
a) Contact process b) Haber process
c) Solvay process ✅ d) Chlor-alkali process
Explanation:
In the Solvay process, ammonia, carbon dioxide, and brine (NaCl solution) react to produce sodium carbonate (Na₂CO₃) — washing soda.
Equation:
NaCl + NH₃ + CO₂ + H₂O → NaHCO₃ + NH₄Cl
2NaHCO₃ → Na₂CO₃ + CO₂ + H₂O (on heating)