MCQs on Acids, Bases, and Salts
1. Which of the following acids is an organic acid?
A) HCl
B) H2SO4
C) CH3COOH ✅
D) HNO3
2. Which acid is dibasic?
A) HCl
B) H2SO4 ✅
C) HNO3
D) CH3COOH
3. A strong acid is one that:
A) Dissociates partially in water
B) Furnishes OH⁻ ions
C) Dissociates almost completely to give H₃O⁺ ✅
D) Contains carbon
4. Which acid has basicity 3?
A) HCl
B) H2SO4
C) H3PO4 ✅
D) CH3COOH
5. If the degree of ionization is 25%, the acid is:
A) Strong
B) Weak ✅
C) Neutral
D) Amphoteric
6. Which gas burns with a pop sound when acids react with metals?
A) CO₂
B) H₂ ✅
C) SO₂
D) H₂S
7. The colour of methyl orange in a basic solution is:
A) Red
B) Yellow ✅
C) Green
D) Blue
8. Which is a volatile acid?
A) H₂SO₄
B) HCl ✅
C) H₃PO₄
D) H₂CO₃
9. SO₃ + H₂O → ?
A) H₂SO₃
B) H₂SO₄ ✅
C) H₂CO₃
D) H₃PO₄
10. Which reaction produces CO₂ gas?
A) Acid + carbonate ✅
B) Acid + base
C) Acid + sulphide
D) Acid + sulphite
11. The smell of burning sulphur is due to:
A) SO₂ ✅
B) H₂S
C) CO₂
D) NO₂
12. Which gas has a rotten egg smell?
A) SO₂
B) CO₂
C) H₂S ✅
D) NO₂
13. Which of the following is a strong alkali?
A) NH₄OH
B) NaOH ✅
C) Ca(OH)₂
D) Mg(OH)₂
14. Which base is diacidic?
A) NaOH
B) KOH
C) Ca(OH)₂ ✅
D) Al(OH)₃
15. Which base is formed by dissolving CaO in water?
A) CaCO₃
B) Ca(OH)₂ ✅
C) CaSO₄
D) CaCl₂
16. 2Na + 2H₂O → ?
A) Na₂O + H₂
B) NaOH + H₂ ✅
C) Na₂O₂ + H₂O
D) NaHCO₃
17. Which is prepared by precipitation reaction?
A) NaOH
B) Ca(OH)₂ ✅
C) KOH
D) Na₂O
18. Which metal oxide is formed by oxidation of ZnS?
A) ZnO ✅
B) ZnCO₃
C) ZnSO₄
D) Zn(NO₃)₂
19. pH of a neutral solution at 25°C is:
A) 0
B) 7 ✅
C) 14
D) 1
20. What is the pH of a strong alkali likely to be?
A) <7
B) =7
C) >7 ✅
D) 0
21. If pH decreases, the solution becomes:
A) More basic
B) More acidic ✅
C) Neutral
D) Diluted
22. Salt of strong acid and weak base is:
A) Neutral
B) Acidic ✅
C) Alkaline
D) Amphoteric
23. Which acid is found in bee sting?
A) Formic acid ✅
B) Acetic acid
C) Citric acid
D) Oxalic acid
24. Wasp stings are:
A) Acidic
B) Alkaline ✅
C) Neutral
D) Amphoteric
25. Which compound is used to neutralise a bee sting?
A) Baking soda ✅
B) Vinegar
C) HCl
D) NaOH
26. Which salt is normal salt?
A) NaHSO₄
B) NaCl ✅
C) NaHCO₃
D) Pb(OH)Cl
27. Which salt is basic salt?
A) Na₂SO₄
B) Pb(OH)Cl ✅
C) NaCl
D) NaHSO₃
28. The colour of phenolphthalein in a basic medium is:
A) Red
B) Pink ✅
C) Colourless
D) Yellow
29. Which reaction produces ammonia?
A) NH₄Cl + NaOH ✅
B) Na₂CO₃ + HCl
C) Zn + H₂SO₄
D) NaCl + H₂O
30. Which universal indicator colour indicates strong acid?
A) Violet
B) Green
C) Red ✅
D) Yellow
31. The oxide of a non-metal reacting with water to give an acid is called:
A) Basic oxide
B) Acidic oxide ✅
C) Amphoteric oxide
D) Neutral oxide
32. CaCO₃ → CaO + CO₂ is an example of:
A) Synthesis
B) Decomposition ✅
C) Neutralisation
D) Double displacement
33. Which gas turns lime water milky but has no effect on acidified KMnO₄?
A) CO₂ ✅
B) SO₂
C) H₂S
D) NO₂
34. Which gas turns acidified potassium dichromate solution from orange to green?
A) CO₂
B) SO₂ ✅
C) H₂S
D) NH₃
35. The number of OH⁻ ions per molecule of Al(OH)₃ is:
A) 1
B) 2
C) 3 ✅
D) 4
36. H₂SO₄ is:
A) Dibasic ✅
B) Monobasic
C) Tribasic
D) Tetrabasic
37. NaHSO₄ is:
A) Normal salt
B) Acid salt ✅
C) Basic salt
D) Neutral salt
38. Which metal reacts with cold water to form hydroxide and hydrogen?
A) Na ✅
B) Mg
C) Zn
D) Fe
39. NH₄OH is:
A) Strong alkali
B) Weak alkali ✅
C) Neutral salt
D) Acid
40. Which reaction is a neutralisation?
A) NaOH + HCl → NaCl + H₂O ✅
B) CaCO₃ → CaO + CO₂
C) Zn + H₂SO₄ → ZnSO₄ + H₂
D) Na₂O + H₂O → NaOH
41. Which compound is tetrabasic acid?
A) H₃PO₄
B) H₄P₂O₇ ✅
C) H₂SO₄
D) HNO₃
42. Which of the following is a monoacidic base?
A) NaOH ✅
B) Ca(OH)₂
C) Mg(OH)₂
D) Al(OH)₃
43. Which of these is an oxyacid?
A) HI
B) HNO₃ ✅
C) HCl
D) HF
44. Which acid is non-volatile?
A) HCl
B) H₂SO₄ ✅
C) HNO₃
D) CH₃COOH
45. Which gas has a choking smell?
A) CO₂
B) SO₂ ✅
C) H₂S
D) NH₃
46. Which oxide is produced from Fe + steam at red heat?
A) FeO
B) Fe₂O₃
C) Fe₃O₄ ✅
D) Fe(OH)₃
47. Which salt is alkaline in nature?
A) Na₂CO₃ ✅
B) NaCl
C) NH₄Cl
D) NaNO₃
48. Which chemical is used to prepare nitrate salts?
A) HNO₃ ✅
B) HCl
C) H₂SO₄
D) Na₂CO₃
49. P₂O₅ + H₂O → ?
A) H₃PO₄ ✅
B) H₂SO₄
C) H₃PO₃
D) HNO₃
50. Which acid is used in car batteries?
A) HCl
B) HNO₃
C) H₂SO₄ ✅
D) CH₃COOH
Case 1 — Ionic Bonding in NaCl
Sodium reacts with chlorine to form sodium chloride. Sodium loses one electron from its outer shell to form Na⁺, and chlorine gains one electron to form Cl⁻. The oppositely charged ions are held together by strong electrostatic forces. NaCl has a high melting point and is soluble in water.
- Write the electronic configurations of Na and Cl.
- Name the type of bond formed in NaCl.
- Will NaCl conduct electricity in solid state? Why/Why not?
- Give one reason for NaCl’s high melting point.
- Draw the electron dot structure for NaCl.
Case 2 — Covalent Bonding in H₂O
Water is formed when hydrogen shares its single electron with oxygen, and oxygen shares one of its electrons with each hydrogen. The shared electron pairs form covalent bonds. Water is polar, has a high boiling point, and is a universal solvent.
- Name the type of covalent bond between H and O.
- Why is water polar?
- Does pure water conduct electricity?
- Draw the electron dot structure of water.
- Give one reason for water’s high boiling point.
Case 3 — Coordinate Bond in NH₄⁺
In an ammonium ion, NH₃ donates a lone pair of electrons to an H⁺ ion, forming a coordinate bond. The NH₄⁺ ion combines with Cl⁻ to form NH₄Cl, which contains covalent, ionic, and coordinate bonds.
- Name the donor atom in the coordinate bond of NH₄⁺.
- What type of ion is NH₄⁺ — cation or anion?
- Write the condition necessary for a coordinate bond to form.
- Give one everyday use of NH₄Cl.
- Is NH₄Cl soluble in water? Why?
Case 4 — Ionic Bonding in MgCl₂
Magnesium loses two electrons to form Mg²⁺, which bonds with two Cl⁻ ions. MgCl₂ is crystalline, has a high melting point, and conducts electricity in molten state.
- How many chlorine atoms bond with one magnesium atom?
- Name the type of bond in MgCl₂.
- Why does MgCl₂ conduct electricity in molten form but not in solid form?
- Draw the electron dot structure of MgCl₂.
- State one use of MgCl₂.
Case 5 — Properties of Ionic vs Covalent Compounds
A compound X is hard, soluble in water, and conducts electricity when dissolved. Compound Y is soft, insoluble in water, and does not conduct electricity.
- Identify X and Y as ionic or covalent.
- Which type of bond is present in X?
- Which type of bond is present in Y?
- Which compound will have a lower melting point?
- Give one use of ionic compounds.
Case 6 — Bonding in CO₂
Carbon dioxide consists of one carbon atom double-bonded to two oxygen atoms. It is a linear molecule, covalent in nature, and acidic in water.
- State the type of bond between C and O in CO₂.
- Is CO₂ ionic or covalent?
- Write the reaction of CO₂ with water.
- Why is CO₂ considered acidic in nature?
- Draw the electron dot structure of CO₂.
Case 7 — Polar vs Non-Polar Molecules
Hydrogen chloride (HCl) is polar, while chlorine (Cl₂) is non-polar. In HCl, the shared electron pair is displaced towards chlorine due to its higher electronegativity.
- Why is HCl polar?
- Why is Cl₂ non-polar?
- Name the type of bond in HCl.
- Which will have higher boiling point — HCl or Cl₂? Why?
- Does HCl dissolve in water? Why?
Case 8 — Covalent Bonding in Methane
In methane (CH₄), carbon shares its four valence electrons with four hydrogen atoms, forming four single covalent bonds. Methane is a major component of natural gas and is non-polar.
- Draw the electron dot structure of CH₄.
- State the type of bond in CH₄.
- Is CH₄ polar or non-polar?
- Why is CH₄ insoluble in water?
- Give one use of methane.
Case 9 — Ionic Nature of Metal Oxides
Sodium oxide (Na₂O) reacts with water to form NaOH, a strong base. Na₂O is ionic in nature.
- Write the reaction of Na₂O with water.
- Why is Na₂O ionic?
- Name the type of solution formed when Na₂O dissolves in water.
- Is Na₂O acidic, basic, or amphoteric?
- Give one use of NaOH.
Case 10 — Bonding in Graphite
Graphite consists of layers of carbon atoms arranged in hexagons. Each carbon atom forms three covalent bonds, with one free electron that moves freely, allowing conduction of electricity.
- How many covalent bonds does each carbon atom form in graphite?
- Why does graphite conduct electricity?
- Is graphite ionic or covalent?
- Name one use of graphite based on its conductivity.
- How does the structure of graphite differ from diamond?
Case 11:
Read the following and answer:
When sodium reacts with chlorine, sodium loses one electron to form Na⁺, while chlorine gains one electron to form Cl⁻. The resulting compound NaCl is solid, hard, and has a high melting point.
- Name the type of bond formed in NaCl.
- Why does Na lose one electron while Cl gains one?
- Write the electron dot structure for NaCl.
- State whether NaCl will conduct electricity in solid state.
- Why does NaCl dissolve in water?
Case 12:
Read and answer:
In a water molecule, each hydrogen shares one electron with oxygen, and oxygen shares one electron with each hydrogen atom, forming shared pairs of electrons.
- Name the type of bond present in water.
- Is water a polar or non-polar covalent compound?
- Why does water have a high boiling point compared to H₂?
- State whether water conducts electricity in pure form.
- Draw the electron dot structure of water.
Case 13:
Read and answer:
Ammonium chloride (NH₄Cl) contains covalent bonds, ionic bonds, and a coordinate bond.
- Name the ions present in NH₄Cl.
- Which bond in NH₄Cl is a coordinate bond?
- Write the condition necessary for a coordinate bond to form.
- State one use of NH₄Cl.
- Is NH₄Cl soluble in water? Why?
Case 14:
Read and answer:
Magnesium reacts with chlorine to form MgCl₂, an ionic compound.
- How many electrons does Mg lose to form Mg²⁺?
- How many Cl atoms are needed to balance Mg²⁺?
- Write the electron dot structure of MgCl₂.
- Will MgCl₂ conduct electricity in molten form?
- Why does MgCl₂ have a high melting point?
10 Application-Based Questions
- Lithium forms LiF while carbon forms CH₄. Explain the reason for the difference in bonding.
- Why is CO₂ a covalent compound even though it contains double bonds?
- Explain why graphite conducts electricity while diamond does not, even though both are covalent.
- A student says that all compounds containing hydrogen are covalent. Give one example to prove the statement wrong.
- Why is NaCl solid at room temperature, while CH₄ is a gas?
- If potassium has a low ionization potential, what type of bond will it most likely form with chlorine?
- Why does ice float on water even though both contain covalent bonds?
- Why does NH₃ act as a Lewis base in the formation of [Cu(NH₃)₄]²⁺?
- Why does CaO conduct electricity in molten form but not in solid form?
- A compound is found to be hard, soluble in water, and conducts electricity when dissolved. Predict its bonding type and justify your answer.
