Class 8 Science · Original EZT practice
Solutes, Solvents, and Solutions (Class 8 Science Chapter 9): what really happens when something dissolves
Salt vanishes in water, sand refuses to, and lemon sherbet only tastes right when the sugar is fully dissolved. This chapter names the players - solute, solvent, solution - and explains why some things dissolve, why heating helps, and what "saturated" really means. Below: the ideas in plain words, then original EZT practice with worked answers. (Note: this is original practice, not a textbook exercise key.)
10 original worked examples, 10 fresh self-check questions, with explained answers. These are not copied textbook exercises, an official chapter index or a full answer key. No affiliation with NCERT is claimed.
Official sources for topic and edition context, checked 17 October 2026:
1. Solute + solvent = solution
The substance that dissolves is the solute; the one that does the dissolving is the solvent; the uniform mixture formed is the solution. In salt water: salt is the solute, water the solvent, salt water the solution. Water is called the universal solvent because it dissolves so many substances.
2. Soluble and insoluble
A solute that dissolves in a solvent is soluble in it; one that does not is insoluble. Solubility is specific to the pair: salt dissolves in water but not in oil; grease dissolves in petrol but not in water.
3. How much can dissolve: solubility and saturation
A solvent can hold only so much solute at a given temperature. When no more will dissolve, the solution is saturated; before that it is unsaturated. The maximum amount that dissolves is the solute's solubility at that temperature.
4. Dissolving faster: heat, stir, powder
Three levers speed up dissolving: heating the solvent, stirring, and crushing the solute into smaller pieces (more surface touches the solvent).
5. Solutions all around us
Air is a solution of gases (oxygen dissolved in nitrogen and other gases); soda water is carbon dioxide dissolved in water under pressure; brass is a "solution" of two solids - zinc dissolved in copper. Solutions are not always liquids.
Choose, solve, check, then try a fresh question.
Before calculating, read the method prompt and name the condition that makes it useful. Write your own attempt. Open the steps only when you need them, and use the check to catch a wrong sign, unit or interpretation. Finish with the fresh question before reading its answer.
In lemon sherbet made with sugar, lemon juice and water, name the solvent...
Choose the method: The substance that dissolves is the solute; the one that does the dissolving is the solvent; the uniform mixture formed is the solution.
EZT practice question
In lemon sherbet made with sugar, lemon juice and water, name the solvent and one solute.
Show the worked solution
- Identify the solute, solvent, mixture or condition being changed.
- Use solubility, saturation, temperature, stirring or surface area to reason it through.
- State the result with the substance and condition named.
Answer: water is the solvent; sugar (and the lemon juice) are solutes.
Check: The solute, solvent and condition in the conclusion match the worked example.
Watch for this: Do not treat solubility as a property of the solute alone; it always depends on the solute-solvent pair and the temperature.
Now try it yourself
Create one new example by changing the substance, activity or body response and solve it by the same test.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
Why is water called the universal solvent?
Choose the method: The substance that dissolves is the solute; the one that does the dissolving is the solvent; the uniform mixture formed is the solution.
EZT practice question
Why is water called the universal solvent?
Show the worked solution
- Identify the solute, solvent, mixture or condition being changed.
- Use solubility, saturation, temperature, stirring or surface area to reason it through.
- State the result with the substance and condition named.
Answer: because it dissolves a wider variety of substances than any other common liquid - from salt and sugar to gases like oxygen that fish breathe.
Check: The solute, solvent and condition in the conclusion match the worked example.
Watch for this: Do not treat solubility as a property of the solute alone; it always depends on the solute-solvent pair and the temperature.
Now try it yourself
Create one new example by changing the substance, activity or body response and solve it by the same test.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
Sand mixed in water settles at the bottom. Is sand soluble in water?
Choose the method: A solute that dissolves in a solvent is soluble in it; one that does not is insoluble.
EZT practice question
Sand mixed in water settles at the bottom. Is sand soluble in water?
Show the worked solution
- Identify the solute, solvent, mixture or condition being changed.
- Use solubility, saturation, temperature, stirring or surface area to reason it through.
- State the result with the substance and condition named.
Answer: no - it is insoluble; the mixture is not a true solution, and the sand can be filtered back out.
Check: The solute, solvent and condition in the conclusion match the worked example.
Watch for this: Do not treat solubility as a property of the solute alone; it always depends on the solute-solvent pair and the temperature.
Now try it yourself
Create one new example by changing the substance, activity or body response and solve it by the same test.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
A grease stain will not wash out with plain water but comes off with petrol...
Choose the method: A solute that dissolves in a solvent is soluble in it; one that does not is insoluble.
EZT practice question
A grease stain will not wash out with plain water but comes off with petrol. Explain.
Show the worked solution
- Identify the solute, solvent, mixture or condition being changed.
- Use solubility, saturation, temperature, stirring or surface area to reason it through.
- State the result with the substance and condition named.
Answer: grease is insoluble in water but soluble in petrol - solubility depends on the solute-solvent pair.
Check: The solute, solvent and condition in the conclusion match the worked example.
Watch for this: Do not treat solubility as a property of the solute alone; it always depends on the solute-solvent pair and the temperature.
Now try it yourself
Create one new example by changing the substance, activity or body response and solve it by the same test.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
You keep adding salt to a glass of water, stirring each time, until some...
Choose the method: A solvent can hold only so much solute at a given temperature.
EZT practice question
You keep adding salt to a glass of water, stirring each time, until some stays undissolved at the bottom. What is the solution now called?
Show the worked solution
- Identify the solute, solvent, mixture or condition being changed.
- Use solubility, saturation, temperature, stirring or surface area to reason it through.
- State the result with the substance and condition named.
Answer: saturated - the water is holding all the salt it can at that temperature.
Check: The solute, solvent and condition in the conclusion match the worked example.
Watch for this: Do not treat solubility as a property of the solute alone; it always depends on the solute-solvent pair and the temperature.
Now try it yourself
Create one new example by changing the substance, activity or body response and solve it by the same test.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
How could you make the undissolved salt in Worked Example 5 disappear...
Choose the method: A solvent can hold only so much solute at a given temperature.
EZT practice question
How could you make the undissolved salt in Worked Example 5 disappear without adding more water?
Show the worked solution
- Identify the solute, solvent, mixture or condition being changed.
- Use solubility, saturation, temperature, stirring or surface area to reason it through.
- State the result with the substance and condition named.
Answer: warm the solution - solubility of most solid solutes increases with temperature, so the warm water can hold more.
Check: The solute, solvent and condition in the conclusion match the worked example.
Watch for this: Do not treat solubility as a property of the solute alone; it always depends on the solute-solvent pair and the temperature.
Now try it yourself
Create one new example by changing the substance, activity or body response and solve it by the same test.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
Why does sugar dissolve faster in hot tea than in cold?
Choose the method: Three levers speed up dissolving: heating the solvent, stirring, and crushing the solute into smaller pieces (more surface touches the solvent).
EZT practice question
Why does sugar dissolve faster in hot tea than in cold?
Show the worked solution
- Identify the solute, solvent, mixture or condition being changed.
- Use solubility, saturation, temperature, stirring or surface area to reason it through.
- State the result with the substance and condition named.
Answer: at higher temperature the solvent particles move faster and can take up solute more quickly - and more of it.
Check: The solute, solvent and condition in the conclusion match the worked example.
Watch for this: Do not treat solubility as a property of the solute alone; it always depends on the solute-solvent pair and the temperature.
Now try it yourself
Create one new example by changing the substance, activity or body response and solve it by the same test.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
Why do we crush sugar cubes (or use powdered sugar) when making sherbet?
Choose the method: Three levers speed up dissolving: heating the solvent, stirring, and crushing the solute into smaller pieces (more surface touches the solvent).
EZT practice question
Why do we crush sugar cubes (or use powdered sugar) when making sherbet?
Show the worked solution
- Identify the solute, solvent, mixture or condition being changed.
- Use solubility, saturation, temperature, stirring or surface area to reason it through.
- State the result with the substance and condition named.
Answer: smaller pieces expose far more surface area to the water, so the sugar dissolves much faster.
Check: The solute, solvent and condition in the conclusion match the worked example.
Watch for this: Do not treat solubility as a property of the solute alone; it always depends on the solute-solvent pair and the temperature.
Now try it yourself
Create one new example by changing the substance, activity or body response and solve it by the same test.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
Soda water fizzes when opened. What is the solute, and why does it escape?
Choose the method: Air is a solution of gases (oxygen dissolved in nitrogen and other gases); soda water is carbon dioxide dissolved in water under pressure; brass is a "solution" of two solids - zinc dissolved in copper.
EZT practice question
Soda water fizzes when opened. What is the solute, and why does it escape?
Show the worked solution
- Identify the solute, solvent, mixture or condition being changed.
- Use solubility, saturation, temperature, stirring or surface area to reason it through.
- State the result with the substance and condition named.
Answer: carbon dioxide gas - it was dissolved under pressure, and opening the bottle drops the pressure so the gas comes out.
Check: The solute, solvent and condition in the conclusion match the worked example.
Watch for this: Do not treat solubility as a property of the solute alone; it always depends on the solute-solvent pair and the temperature.
Now try it yourself
Create one new example by changing the substance, activity or body response and solve it by the same test.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
Is air a solution? Explain.
Choose the method: Air is a solution of gases (oxygen dissolved in nitrogen and other gases); soda water is carbon dioxide dissolved in water under pressure; brass is a "solution" of two solids - zinc dissolved in copper.
EZT practice question
Is air a solution? Explain.
Show the worked solution
- Identify the solute, solvent, mixture or condition being changed.
- Use solubility, saturation, temperature, stirring or surface area to reason it through.
- State the result with the substance and condition named.
Answer: yes - it is a uniform mixture of gases (mainly oxygen dissolved in nitrogen), a solution where the solvent itself is a gas.
Check: The solute, solvent and condition in the conclusion match the worked example.
Watch for this: Do not treat solubility as a property of the solute alone; it always depends on the solute-solvent pair and the temperature.
Now try it yourself
Create one new example by changing the substance, activity or body response and solve it by the same test.
Check your answer
Keep the final result in your notebook; the page-level Try It prompts are intentionally answer-free.
The worked answer above shows the method; independent practice should not become another answer key.
Try it yourself
Work these on paper before checking any notes. Answers are deliberately not shown here.
- Identify solute, solvent and solution in glucose water.
- Name one substance soluble in water and one insoluble.
- What does a saturated solution mean?
- Give two ways to dissolve salt faster.
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Questions about this practice page
- What is the difference between solute, solvent and solution?
- the solute is what dissolves, the solvent is what dissolves it, and the solution is the uniform mixture they form - salt, water and salt water.
- What is a saturated solution?
- one in which no more solute will dissolve at that temperature - extra solute simply settles at the bottom.
- How does temperature affect dissolving?
- for most solid solutes, heating the solvent increases solubility and speeds dissolving; gases behave oppositely - they come out of solution when warmed or when pressure drops, as in fizzing soda.
- Why is water called the universal solvent?
- because it dissolves more kinds of substances than any other common liquid - solids, liquids and gases alike.
- Are these the NCERT exercise questions for Solutes, Solvents, and Solutions?
- No. EZT pages are original practice on this chapter - use them to prepare for the textbook exercises, not as a substitute for your book.