Background: The strength of an acid refers to its ability or tendency to lose a proton. A strong acid is one that completely dissociates in water; in other words, one mole of a strong acid HA dissolves in water yielding one mole of H+ and one mole of the conjugate base, A−, and none of the protonated acid HA. In contrast, a weak acid only partially dissociates and at equilibrium both the acid and the conjugate base are in solution. Examples of strong acids are hydrochloric acid (HCl), hydroiodic acid (HI), hydrobromic acid (HBr), perchloric acid (HClO4), nitric acid (HNO3) and sulfuric acid (H2SO4). In water each of these essentially ionizes 100%. The stronger an acid is, the more easily it loses a proton, H+. Two key factors that contribute to the ease of deprotonation are the polarity of the H—A bond and the size of atom A, which determines the strength of the H—A bond. Acid strengths are also often discussed in terms of the stability of the conjugate base.

Situation: David is a chemical engineer. Yesterday, he was working on two samples, sample A and sample B. Sample A was a strong acid, and sample B was a weak acid. David needed to find the differences between them.

Question: Which would dissociate in water more, sample A or sample B?
Answer: sample A

Situation: David is a chemical engineer. Yesterday, he was working on two samples, sample A and sample B. Sample A was a strong acid, and sample B was a weak acid. David needed to find the differences between them.

Question: Which would dissociate in water less, sample A or sample B?
Answer: sample B

Situation: David is a chemical engineer. Yesterday, he was working on two samples, sample A and sample B. Sample A was a strong acid, and sample B was a weak acid. David needed to find the differences between them.

Question: Would sample A dissociate in water less or more than sample B?
Answer: more

Situation: David is a chemical engineer. Yesterday, he was working on two samples, sample A and sample B. Sample A was a strong acid, and sample B was a weak acid. David needed to find the differences between them.

Question: Would sample B dissociate in water less or more than sample A?
Answer: less

Situation: David is a chemical engineer. Yesterday, he was working on two samples, sample A and sample B. Sample A was a strong acid, and sample B was a weak acid. David needed to find the differences between them.

Question: Which would lose a proton more easily, sample A or sample B?
Answer: sample A

Situation: David is a chemical engineer. Yesterday, he was working on two samples, sample A and sample B. Sample A was a strong acid, and sample B was a weak acid. David needed to find the differences between them.

Question: Which would lose a proton less easily, sample A or sample B?
Answer: sample B

Situation: David is a chemical engineer. Yesterday, he was working on two samples, sample A and sample B. Sample A was a strong acid, and sample B was a weak acid. David needed to find the differences between them.

Question: Would sample A lose a proton less or more easily than sample B?
Answer: more

Situation: David is a chemical engineer. Yesterday, he was working on two samples, sample A and sample B. Sample A was a strong acid, and sample B was a weak acid. David needed to find the differences between them.

Question: Would sample B lose a proton less or more easily than sample A?
Answer: less

Situation: David is a chemical engineer. Yesterday, he was working on two samples, sample A and sample B. Sample A was a strong acid, and sample B was a weak acid. David needed to find the differences between them.

Question: Which would fully ionize in water, sample A or sample B?
Answer: sample A

Situation: David is a chemical engineer. Yesterday, he was working on two samples, sample A and sample B. Sample A was a strong acid, and sample B was a weak acid. David needed to find the differences between them.

Question: Which would partially ionize in water, sample A or sample B?
Answer: sample B