Acids and Alkalis

Question 1

Acid

Answer 1

A substance that donates protons (H⁺) in a solution and has a pH less than 7.

Question 2

Alkali

Answer 2

A subset of bases that are soluble in water and produce hydroxide ions (OH⁻) in solution; they have a pH greater than 7.

Question 3

pH Scale

Answer 3

A scale ranging from 0 to 14 that measures the acidity or alkalinity of a solution; 7 is neutral, less than 7 is acidic, and greater than 7 is alkaline.

Question 4

Neutralization Reaction

Answer 4

A chemical reaction between an acid and a base (alkali) that produces water and a salt.

Question 5

Strong Acid

Answer 5

An acid that completely ionises in water to form H+ ions (e.g., hydrochloric acid, HCl).

Question 6

Weak Acid

Answer 6

An acid that only partially ionises in water to form H+ ions (e.g., acetic acid, CH₃COOH).

Question 7

Strong Alkali

Answer 7

An alkali that completely ionise in water to form OH- ions (e.g., sodium hydroxide, NaOH).

Question 8

Weak Alkali

Answer 8

An alkali that only partially ionises in water to produce OH- ions (e.g., ammonia, NH₃).

Question 9

Indicators

Answer 9

Substances that change color in response to changes in pH, used to determine whether a solution is acidic or alkaline (e.g., litmus, phenolphthalein).

Question 10

Monobasic Acid

Answer 10

Only produces 1 H+ ion when being ionised in water e.g. Hydrochloric acid (HCl)

Question 11

Dibasic Acid

Answer 11

Produces 2 H+ ions when being ionised in water e.g. Sulfuric acid (H₂SO₄)