Acid Examples in Chemistry

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Acid.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Chemistry.

Concept Recap

A substance that donates \text{H}^+ ions (protons) when dissolved in water, increasing the hydrogen ion concentration and lowering the pH below 7. Under the Bronsted-Lowry definition, any proton donor is an acid.

Sour-tasting substances that can 'burn'—they give away hydrogen ions.

Read the full concept explanation →

How to Use These Examples

  • Read the first worked example with the solution open so the structure is clear.
  • Try the practice problems before revealing each solution.
  • Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: Acids increase \text{H}^+ concentration in water, resulting in a pH below 7.

Common stuck point: Strong acids fully dissociate; weak acids only partially dissociate.

Sense of Study hint: When identifying an acid, look for substances that release \text{H}^+ in water. First check the formula for hydrogen atoms bonded to electronegative atoms (like \text{HCl}, \text{H}_2\text{SO}_4). Then determine if it is strong (fully dissociates) or weak (partially dissociates) by checking the common strong acid list. Finally, for calculations use K_a for weak acids.

Worked Examples

Example 1

easy
According to the Arrhenius definition, what makes a substance an acid? Give two examples.

Solution

  1. 1
    An Arrhenius acid produces \text{H}^+ ions (protons) when dissolved in water.
  2. 2
    Example 1: \text{HCl} \rightarrow \text{H}^+ + \text{Cl}^- (hydrochloric acid).
  3. 3
    Example 2: \text{H}_2\text{SO}_4 \rightarrow 2\text{H}^+ + \text{SO}_4^{2-} (sulfuric acid).

Answer

\text{Acids produce H}^+\text{ in water: HCl, H}_2\text{SO}_4
The Arrhenius definition is the simplest model for acids. The Brønsted-Lowry definition extends this to any proton donor, even in non-aqueous solvents.

Example 2

medium
Distinguish between a strong acid and a weak acid. Give an example of each.

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

easy
Name three common strong acids.

Example 2

easy
What particle does an acid donate in solution, and how does that affect the hydrogen-ion concentration of the solution?
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Related Concepts

IonBasepHNeutralization

Background Knowledge

These ideas may be useful before you work through the harder examples.

ion