Solubility Examples: 46 Problems with Answers

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

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

Concept Recap

The maximum amount of a solute that can dissolve in a given quantity of solvent at a specific temperature and pressure, typically expressed as grams.

How much can dissolve before no more will. Sugar: high solubility. Sand: zero.

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: Solubility starts by identifying solute, solvent, amount, volume, and the concentration unit.

Common stuck point: Students often know a formula related to solubility but skip the recognition step: Am I tracking solute, solvent, total solution, concentration, dissolving, or dilution rather than just naming a mixture? That leads to a correct-looking substitution attached to the wrong chemical model.

Sense of Study hint: Ask: Am I tracking solute, solvent, total solution, concentration, dissolving, or dilution rather than just naming a mixture?

Worked Examples

Example 1

easy

Define solubility and explain how temperature generally affects the solubility of solids and gases in water.

Answer

Solids: solubility increases with T. Gases: solubility decreases with T.

First step

Solubility is the maximum amount of solute that dissolves in a given amount of solvent at a specific temperature, usually expressed in

\text{g/100 g water}

\text{g/L}

Full solution

2
For most solid solutes: solubility increases with increasing temperature (e.g., sugar dissolves faster in hot water).
3
For gaseous solutes: solubility decreases with increasing temperature (e.g., warm soda goes flat because dissolved $\text{CO}_2$ escapes).

Temperature affects the kinetic energy of particles. For solids, higher temperature helps overcome the lattice energy holding the solid together. For gases, higher temperature gives gas molecules enough energy to escape the liquid.

Example 2

medium

Using a solubility curve, determine how many grams of

\text{KClO}_3

can dissolve in

100

g of water at

80°\text{C}

if the solubility is

40\,\text{g/100 g water}

. If the solution is cooled to

30°\text{C}

where the solubility is

10\,\text{g/100 g water}

, how much crystallizes out?

Example 3

medium

60°\text{C}

\text{KNO}_3

solubility is

110\,\text{g}/100\,\text{g}

water. A saturated solution is prepared with

250\,\text{g}

water at

60°\text{C}

, then cooled to

20°\text{C}

where solubility is

32\,\text{g}/100\,\text{g}

water. How many grams of

\text{KNO}_3

crystallize out?

Example 4

medium

At what temperature reading does a solubility curve cross from solid behavior to gas behavior in terms of temperature dependence? Explain why the two slope signs differ.

Example 5

medium

80°\text{C}

\text{KBr}

solubility is

95\,\text{g}/100\,\text{g}

. A chemist saturates

150\,\text{g}

water at

80°\text{C}

, cools to

20°\text{C}

where solubility is

65\,\text{g}/100\,\text{g}

. Find the mass of crystals.

Example 6

hard

A student prepares

200\,\text{g}

of saturated

\text{NaCl}

solution at

20°\text{C}

(solubility

36\,\text{g}/100\,\text{g}

water). Calculate the mass of

\text{NaCl}

and mass of water in the solution.

Example 7

hard

Why is hot tap water generally a poor source of drinking water for fish? Connect three ideas: gas solubility, temperature, and dissolved

\text{O}_2

Example 8

challenge

Common-ion effect:

\text{AgCl}

has

K_{sp} = 1.8 \times 10^{-10}

. Find the molar solubility of

\text{AgCl}

0.10\,\text{M}

\text{NaCl}

solution.

Practice Problems

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

Example 1

medium

25°\text{C}

, the solubility of

\text{CaSO}_4

0.21\,\text{g/100 mL}

. If a student adds

1.0

g of

\text{CaSO}_4

challenge

Gas solubility follows S = k times P. If S = 0.05 mol/L at 2 atm, what is S at 5 atm?

Example 23

easy

A salt has solubility

20\,\text{g}/100\,\text{g}

water at

25°\text{C}

. What is the maximum mass of salt that can dissolve in

300\,\text{g}

of water at

25°\text{C}

Example 24

easy

A bottle of soda is left open on the counter for hours and goes flat. Which property of gas solubility explains this?

Example 25

easy

20°\text{C}

, NaCl solubility is

36\,\text{g}/100\,\text{g}

water. A student dissolves

9\,\text{g}

of NaCl in

25\,\text{g}

of water. Is the solution saturated?

Example 26

easy

A student claims sugar 'isn't there anymore' after stirring into water. What is the correct view in terms of solubility?

Example 27

easy

Which one is INSOLUBLE in water according to standard solubility rules:

\text{KNO}_3

\text{NaCl}

\text{PbCl}_2

\text{Na}_2\text{SO}_4

Example 28

medium

A gas has solubility

0.030\,\text{mol/L}

1.0\,\text{atm}

. By Henry's law, what partial pressure is needed for a solubility of

0.105\,\text{mol/L}

Example 29

medium

A solution has

42\,\text{g}

of salt in

150\,\text{g}

water at

25°\text{C}

. The solubility at

25°\text{C}

30\,\text{g}/100\,\text{g}

. Classify the solution.

Example 30

medium

A solubility curve shows that at

50°\text{C}

the solubility of

\text{NaNO}_3

114\,\text{g}/100\,\text{g}

water. How much

\text{NaNO}_3

saturates

400\,\text{g}

of water?

Example 31

medium

A diver inhales air at

4.0\,\text{atm}

underwater. Dissolved

\text{N}_2

1.0\,\text{atm}

on the surface is

0.65\,\text{mmol/L}

. What is the dissolved

\text{N}_2

in blood at

4.0\,\text{atm}

Example 32

medium

\text{KCl}

solubility is

34.0\,\text{g}/100\,\text{g}

20°\text{C}

. A student dissolves

51\,\text{g}

\text{KCl}

200\,\text{g}

water. Will all dissolve? Justify with numbers.

Example 33

medium

Two solutes A and B both have solubility

40\,\text{g}/100\,\text{g}

25°\text{C}

. A dissolves in 30 s; B dissolves in 5 min. Compare their solubility and dissolving rates.

Example 34

hard

25°\text{C}

\text{Ca(OH)}_2

solubility is

0.165\,\text{g}/100\,\text{mL}

. What is the molar solubility? (

M = 74.1\,\text{g/mol}

)

Example 35

hard

A flask holds

250\,\text{mL}

water saturated with

\text{O}_2

25°\text{C}

and

1.0\,\text{atm}

(

S = 8.3\,\text{mg/L}

). The water warms to

35°\text{C}

where

S = 7.0\,\text{mg/L}

. Mass of

\text{O}_2

released?

Example 36

hard

1.0\,\text{atm}

and

25°\text{C}

, dissolved

\text{CO}_2

in water is

0.034\,\text{mol/L}

. A soda is bottled at

4.0\,\text{atm}

\text{CO}_2

. What volume of

\text{CO}_2

(at STP) would

500\,\text{mL}

of this soda release on opening?

Example 37

hard

A solid has solubility

25\,\text{g}/100\,\text{g}

30°\text{C}

. A student mixes

80\,\text{g}

of solid with

200\,\text{g}

water at

30°\text{C}

, stirs to equilibrium, then filters. What is the mass of dry filtrate (recovered solid)?

Example 38

challenge

25°\text{C}

\text{AgCl}

has

K_{sp} = 1.8 \times 10^{-10}

. Find the molar solubility of

\text{AgCl}

, then convert to

\text{g/L}

(

M = 143.32\,\text{g/mol}

← Back to Solubility Practice Mode

Related Concepts

Solution Precipitation Reaction Dilution

Background Knowledge

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

solution