Practice Acid in Chemistry

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

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Quick Recap

A substance that donates $\text{H}^+$ ions (protons) when dissolved in water, increasing the hydrogen ion concentration and lowering the pH below 7.

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

Showing a random 20 of 50 problems.

Example 1

medium

\text{HNO}_3

ionizes completely. For a

0.001\,\text{M}

solution, find the pH.

HNO₃ is strong: [H⁺] = 10⁻³ M, so pH = 3.

Example 2

challenge

0.20\,\text{M}

weak acid HA gives a pH of

2.85

. Determine

K_a

Example 3

medium

A solution of pH 1 is diluted tenfold with water. Estimate the new pH (strong acid, ignoring water autoionization).

Tenfold dilution shifts [H⁺] from 10⁻¹ to 10⁻², raising pH by one unit.

Example 4

easy

Does 'strong acid' refer to the degree of ionization or the amount of acid per volume?

Example 5

challenge

Explain why pure water is not classified as an acid even though it contains

\text{H}^+

ions.

Example 6

medium

A solution has

[\text{H}^+] = 2.5\times 10^{-3}\,\text{M}

. Find the pH to two decimals.

Example 7

easy

When

\text{HCl}

dissolves in water, write the ions produced.

Example 8

easy

Name one common safe acid found in food.

Example 9

easy

What range of pH values are considered acidic?

Acidic solutions have pH < 7; basic solutions have pH > 7.

Example 10

easy

By the Arrhenius definition, what ion does an acid produce in water?

Example 11

hard

0.0050\,\text{M}

solution of

\text{H}_2\text{SO}_4

(treat both ionizations as complete). Find the pH.

Example 12

medium

50.0\,\text{mL}

sample of

0.20\,\text{M}

HCl is mixed with

50.0\,\text{mL}

of water. What is the pH?

Example 13

easy

Which acid is found in the human stomach to aid digestion?

Example 14

easy

Write the conjugate base of

\text{HBr}

Example 15

hard

How many milliliters of

0.10\,\text{M}

NaOH are needed to neutralize

25.0\,\text{mL}

0.20\,\text{M}

HCl?

Example 16

easy

Classify

\text{HCl}

as a strong or weak acid.

Example 17

medium

Compare

1\,\text{M}

acetic acid (weak) and

1\,\text{M}

HCl (strong). Which has the lower pH and why?

Example 18

medium

What is

[\text{H}^+]

in a solution of pH 5?

Example 19

medium

Which has a lower pH:

0.10\,\text{M}

HCl or

0.10\,\text{M}

HF? Explain in one line.

Example 20

easy

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

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Related Concepts

Ion Base pH Neutralization