Base Examples in Chemistry

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

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 accepts \text{H}^+ ions (protons) or donates \text{OH}^- ions when dissolved in solution, raising the pH above 7. Under the Bronsted-Lowry definition, any proton acceptor is a base.

Slippery substances that can neutralize acids—they remove 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: Bases decrease \text{H}^+ concentration (or increase \text{OH}^-) in water.

Common stuck point: Alkalis are bases that dissolve in water, but not all bases are alkalis.

Sense of Study hint: When you see a substance and need to identify if it is a base, check if it can accept a proton or produce \text{OH}^- in water. First look at the formula for \text{OH} groups or lone pairs. Then test with the Bronsted-Lowry definition: does it accept \text{H}^+? Finally, confirm by checking if its aqueous solution has pH above 7.

Worked Examples

Example 1

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

Solution

  1. 1
    An Arrhenius base produces \text{OH}^- ions (hydroxide) when dissolved in water.
  2. 2
    Example 1: \text{NaOH} \rightarrow \text{Na}^+ + \text{OH}^- (sodium hydroxide).
  3. 3
    Example 2: \text{KOH} \rightarrow \text{K}^+ + \text{OH}^- (potassium hydroxide).

Answer

\text{Bases produce OH}^-\text{ in water: NaOH, KOH}
Bases feel slippery and taste bitter. The Brønsted-Lowry definition broadens this to any proton acceptor, allowing substances like \text{NH}_3 to be classified as bases.

Example 2

medium
Ammonia (\text{NH}_3) is a base but does not contain \text{OH}^-. Using the Brønsted-Lowry definition, explain how \text{NH}_3 acts as a base.

Example 3

medium
Identify whether NaOH is an acid or a base. Write the dissociation equation in water.

Practice Problems

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

Example 1

easy
Is a solution with pH = 12 acidic, neutral, or basic?

Example 2

easy
A base is added to water. What happens to the hydrogen-ion concentration, and why?

Related Concepts

Background Knowledge

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

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