Class 8 Science Chapter 9: The Amazing World of Solutes, Solvents, and Solutions Solutions

NCERT Solutions for Class 8 Science Chapter 9: The Amazing World of Solutes, Solvents, and Solutions (2025-26)

1. State whether the statements given below are True [T] or False [F]. Correct the false statement(s).

1. Oxygen gas is more soluble in hot water rather than in cold water.
2. A mixture of sand and water is a solution.
3. The amount of space occupied by any object is called its mass.
4. An unsaturated solution has more solute dissolved than a saturated solution.
5. The mixture of different gases in the atmosphere is also a solution.

Answer:

• (i) False. Oxygen gas is more soluble in cold water than in hot water.
• (ii) False. A mixture of sand and water is not a solution, it is a heterogeneous mixture.
• (iii) False. The amount of space occupied by any object is called its volume.
• (iv) False. An unsaturated solution has less solute dissolved than a saturated solution.
• (v) True.

2. Fill in the blanks.

1. The volume of a solid can be measured by the method of displacement, where the solid is __________ in water and the ____________ in water level is measured.
2. The maximum amount of _______________ dissolved in _______________ at a particular temperature is called solubility at that temperature.
3. Generally, the density ____________ with increase in temperature.
4. The solution in which glucose has completely dissolved in water ... is called a __________ solution of glucose.

Answer:

• (i) immersed, rise/change
• (ii) solute, solvent
• (iii) decreases
• (iv) saturated

3. You pour oil into a glass containing some water. The oil floats on top. What does this tell you?

• (a) Oil is denser than water
• (b) Water is denser than oil
• (c) Oil and water have the same density
• (d) Oil dissolves in water

Answer: (b) Water is denser than oil.

4. A stone sculpture weighs 225 g and has a volume of 90 cm³. Calculate its density and predict whether it will float or sink in water.

Answer: Density = Mass/Volume = 225 g / 90 cm³ = 2.5 g/cm³. Since the density of water is 1 g/cm³, the stone sculpture (2.5 g/cm³) will sink in water.

5. Which one of the following is the most appropriate statement, ...

Answer: (Content for the full question is missing—please refer to your textbook for details.)

6. Analyse Figs. 9.25a and 9.25b. Why does the unpeeled orange float, while the peeled one sinks? Explain.

Answer: The unpeeled orange floats because the peel contains air pockets, making its overall density less than water. The peeled orange sinks as the air is lost and its density becomes more than that of water.

7. Prepare some questions based on your learnings so far...

Answer: Sample questions:

• What is a saturated solution?
• How does temperature affect the solubility of solids?
• Why does ice float on water?

Understanding Solutes, Solvents, and Solutions in Class 8 Science

Mastering the basics of solutes, solvents, and solutions is essential for scoring well in Class 8 Science Chapter 9. This chapter helps you identify how substances mix, why some dissolve and others don't, and why density matters for floating or sinking.

By exploring NCERT Class 8 Science Chapter 9 solutions, students can build conceptual clarity about mixtures, concentration, and measuring density. Focus on key topics like solubility, the effect of temperature, and how to calculate density for competitive exam preparation.

Regular practice of exercise-based questions boosts your confidence before exams. Revise important definitions, formulas, and real-life examples to enhance your understanding and improve your performance in school assessments.