Acids and bases

Question 1

Define the term strong acid. (L.C)

Answer 1

An acid that fully dissociates in solution and is a good proton donor.

Question 2

Define the term dibasic acid. (L.C)

Answer 2

A dibasic acid produces two H⁺ ions in solution e.g. H₂SO₄.

Question 3

Define acid (Bronsted-Lowry theory) (L.C)

Answer 3

An acid is a proton (H⁺) donor.

Question 4

Define conjugate pair (Bronsted-Lowry theory) (L.C)

Answer 4

Two substances that differ by one proton.

Question 5

What is the conjugate base of nitric acid :

4HNO₃ → 2H₂O + 4NO₂ + O₂ (L.C)

Answer 5

NO₃-

Question 6

Define acid according to the Bronsted-Lowry theory.(L.C)

Answer 6

An acid is a proton (H⁺) donor.

Question 7

Define base according to the Bronsted-Lowry theory . (L.C)

Answer 7

A base is a proton (H⁺) acceptor.

Question 8

Identify the acid, and conjugate acid in the following system: H₂S + O²- ⇾ OH- + SH- (L.C)

Answer 8

H₂S (both are acids and both are conjugate bases)

OH-

Question 9

Write (i) the conjugate acid and (ii) the conjugate base of HPO₄²-. (L.C)

Answer 9

Conjugate acid - H₂PO₄-

Conjugate base - PO₄³-

Question 10

Identify one species acting as an acid, and also identify its conjugate base in the following system : H₂F⁺ + Cl- ⇌ HCl + HF

Answer 10

(must match correct one)
Acid - H₂F⁺ / HCl
Conjugate base - HF / Cl-

Question 11

Distinguish between a strong acid and a weak acid. (L.C)

Answer 11

Strong acid - an ad that fully dissociates in solution and is a good proton donor.
Weak acid - an acid that is a poor proton donor and only slightly dissociated in solution.

Question 12

Distinguish between a strong acid and a weak acid. (L.C)

Answer 12

Strong acid - an ad that fully dissociates in solution and is a good proton donor.
Weak acid - an acid that is a poor proton donor and only slightly dissociated in solution.

Question 13

Define acid according to the theory of Bronsted-Lowry. (L.C)

Answer 13

An acid is a proton (H⁺) donor.

Question 14

Distinguish between a strong acid and a weak acid. (L.C)

Answer 14

Strong acid - an acid that fully dissociates in solution and is a good proton donor.
Weak acid - an acid that is a poor proton donor and only slightly dissociated in solution.

Question 15

Identify the two conjugate pairs in the following dissociation of nitrous acid (HNO₂): HNO₂ + H₂O ⇌ NO₂- + H₃O⁺

Answer 15

• HNO₂ and NO₂-

- H₂O and H₃O⁺

Question 16

Define acid according to the Bronsted-Lowry theory. (L.C)

Answer 16

An acid is a proton (H⁺) donor.

Question 17

Define conjugate acid according to the Bronsted-Lowry theory. (L.C)

Answer 17

A base plus a H⁺ ion.

Question 18

Distinguish between a strong acid and a weak acid. (L.C)

Answer 18

Strong acid - an acid that fully dissociates in solution and is a good proton donor.
Weak acid - an acid that is a poor proton donor and only slightly dissociated in solution.

Question 19

Define an acid in terms of the Bronsted-Lowry theory. (L.C)

Answer 19

An acid is a proton (H⁺) donor.

Question 20

What is a conjugate pair? (L.C)

Answer 20

Two substances that differ by one proton.

Question 21

How do strong acids differ from weak acids in their behaviour in water according to the Arrhenius’ theory. (L.C)

Answer 21

Strong : Almost completely dissociated to give hydrogen ions (H⁺) in solution.
Weak : Only slightly dissociated to give hydrogen ions (H⁺) in solution.

Question 22

What is the conjugate base of (i) sulfuric acid, (ii) the weak acid of HA? Which of these conjugate bases is stronger? Explain (L.C) MORE XOXO

Answer 22

(i) HSO₄-
(ii) A-
(iii) A-
(iv) Conjugate base of a weak acid.

Question 23

Explain, by giving a balanced equation for its dissociation in water, that the conjugate base of sulfuric acid is itself an acid. (L.C)

Answer 23

HSO₄- + H₂O ⇾ SO₄²- + H₃O⁺

Question 24

How do strong acids differ from weak acids in their behaviour in water according to the Bronsted-Lowry theory. (L.C)

Answer 24

Strong : good proton (H⁺) donor.

Weak : poor proton (H⁺) donor