Online Test — Acids, Bases and Salts
18 Questions • 15 min • Chapter MCQ
15:00
Question 1 of 18
The ion responsible for the acidic nature of a solution is:
OH⁻
H⁺ (H₃O⁺)
Na⁺
Cl⁻
Explanation: Acids release H+ ions, which exist in water as the hydronium ion H3O+.
Question 2 of 18
Zn + 2HCl → ZnCl2 + ? . The missing product is:
O₂
CO₂
H₂
Cl₂
Explanation: Acid + metal gives salt + hydrogen gas.
Question 3 of 18
The gas produced when an acid reacts with a metal carbonate turns:
lime water milky
blue litmus red
moist starch blue
red litmus blue
Explanation: The gas is CO2, which turns lime water milky.
Question 4 of 18
The net ionic equation for any neutralisation is:
Na⁺ + Cl⁻ → NaCl
H⁺ + OH⁻ → H₂O
H₂ + O₂ → H₂O
CO₂ + H₂O → H₂CO₃
Explanation: Neutralisation is essentially H+ + OH- giving water.
Question 5 of 18
Which solution does NOT conduct electricity?
dilute HCl
NaOH solution
glucose solution
common salt solution
Explanation: Glucose dissolves as neutral molecules with no ions, so it cannot conduct.
Question 6 of 18
The correct way to dilute a concentrated acid is to add:
water to acid rapidly
acid to water slowly with stirring
acid and water at the same time
ice directly to the acid
Explanation: Add acid to water slowly to release the large heat safely and avoid splashing.
Question 7 of 18
The pH of a neutral solution is:
0
7
14
1
Explanation: Pure water is neutral with a pH of 7.
Question 8 of 18
A solution of pH 1 compared with a solution of pH 4 is:
less acidic
more acidic
neutral
basic
Explanation: Lower pH means more H+ ions, so pH 1 is more acidic than pH 4.
Question 9 of 18
Which is a weak acid?
HCl
H₂SO₄
HNO₃
acetic acid
Explanation: Acetic acid ionises only partly in water, so it is a weak acid.
Question 10 of 18
Tooth enamel begins to dissolve when the mouth pH falls below:
7.0
6.5
5.5
3.0
Explanation: Below pH 5.5 the acid is strong enough to attack calcium phosphate enamel.
Question 11 of 18
Phenolphthalein in a basic solution turns:
colourless
pink
red
yellow
Explanation: Phenolphthalein is colourless in acid and turns pink in base.
Question 12 of 18
The antacid used to treat excess stomach acid is:
vinegar
milk of magnesia
lemon juice
common salt
Explanation: Milk of magnesia, Mg(OH)2, is a mild base that neutralises excess HCl.
Question 13 of 18
A salt of a strong acid and a strong base is:
acidic
basic
neutral
amphoteric
Explanation: Such a salt (e.g. NaCl) does not hydrolyse and stays neutral.
Question 14 of 18
The products of the chlor-alkali process are NaOH, H2 and:
oxygen
chlorine
carbon dioxide
ammonia
Explanation: 2NaCl + 2H2O gives 2NaOH + Cl2 + H2.
Question 15 of 18
Bleaching powder is prepared by passing chlorine over:
quicklime
dry slaked lime
limestone
gypsum
Explanation: Ca(OH)2 + Cl2 gives CaOCl2 + H2O.
Question 16 of 18
The chemical name of baking soda is:
sodium carbonate
sodium hydrogencarbonate
sodium hydroxide
sodium chloride
Explanation: Baking soda is sodium hydrogencarbonate, NaHCO3.
Question 17 of 18
Plaster of Paris is:
CaSO₄·2H₂O
CaSO₄·½H₂O
CaCO₃
CaCl₂
Explanation: POP is calcium sulphate hemihydrate, CaSO4.half H2O.
Question 18 of 18
On heating, blue copper sulphate crystals turn white because they lose:
carbon dioxide
oxygen
water of crystallisation
sulphur
Explanation: CuSO4.5H2O loses its water of crystallisation on heating and turns white.