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Week 5 IB Chem SL - Weak and strong acids.

Last updated over 1 year ago

3 questions

4

Question 1

1.

Hydrochloric acid (HCl) is a strong acid, while carbonic acid (H2CO3) is a weak acid.
(a)Explain, with the help of equations, what is meant by strong and weak acid using the above acids as examples.
(b)Outline two ways, other than using pH, in which you could distinguish between carbonic acid and hydrochloric acid of the same concentration.

3

1

Question 2

2.

A solution of hydrochloric acid, HCl(aq), has a pH of 1 and a solution of carbonic acid, H2CO3(aq), has a pH of 5.
(c)Determine the ratio of the hydrogen ion concentrations in these solutions.
(d)The relative strengths of the two acids can be illustrated by the following equation: HCO3−(aq) + HCl(aq) ⇌ H2CO3(aq) + Cl−(aq)
Identify the acid and its conjugate base in this equation; likewise identify the base and its conjugate acid.

Question 3

3.

What is the strongest acid in the equation below?
H3AsO4 + H2O ⇌ H2AsO4− + H3O+ Kc = 4.5 × 10−4

H3AsO4

H2O

H2AsO4 

H3O+