The Amazing World of Solutes, Solvents, and Solutions — Quiz

Q1. Chapter 9 of Class 8 Curiosity expresses the formation of a solution by which of the following word equations?

• A. Solute + Solvent → Solution
• B. Solvent + Solution → Solute
• C. Solute + Solution → Solvent
• D. Solvent + Solute → Mixture

Q2. When a solution is formed by mixing two liquids and one is clearly in smaller amount, that smaller-amount liquid is, by convention, called the

• A. solvent
• B. diluent
• C. saturated component
• D. solute

Q3. A solution in which more solute can still be dissolved at a given temperature is called

• A. a saturated solution
• B. a dilute solution
• C. an unsaturated solution
• D. a concentrated solution

Q4. Ravi prepares two salt solutions: Solution A has 2 spoons of salt in 100 mL water; Solution B has 4 spoons of salt in 50 mL water. Which solution is more concentrated?

• A. Solution A
• B. Solution B
• C. Both are equally concentrated
• D. It cannot be decided without temperature

Q5. Priya keeps stirring salt into a glass of water at room temperature. After some spoons, undissolved salt settles at the bottom and will not dissolve further. This indicates that the solution has become

• A. dilute at that temperature
• B. unsaturated at that temperature
• C. saturated at that temperature
• D. an emulsion

Q6. In Activity 9.2, the beaker has some undissolved baking soda at 20 °C. When the contents are heated to 50 °C with stirring, the undissolved baking soda will

• A. dissolve
• B. remain unchanged
• C. first dissolve, then settle again
• D. evaporate as a gas

Q7. Why can cold river water generally support more fishes than the same volume of warm river water?

• A. Cold water has higher density
• B. Cold water holds more dissolved oxygen
• C. Cold water turns water bodies into uniform mixtures
• D. Cold water has more dissolved salt

Q8. When a teacher pours oil into a glass of water in front of Class 8 students, the oil floats on top. What does this tell the students?

• 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

Q9. A stone sculpture has a mass of 225 g and a volume of 90 cm³. Its density is

• A. 0.4 g/cm³
• B. 2.0 g/cm³
• C. 2.5 g/cm³
• D. 315 g/cm³

Q10. At room temperature, the mass of 1 mL of water is approximately

• A. 0.1 g
• B. 100 g
• C. 10 g
• D. 1 g

Q11. A hot-air balloon rises in the sky on a cool morning. According to Chapter 9, this is because the hot air inside

• A. has a greater mass than the cool air outside
• B. has a smaller volume than the cool air outside
• C. is less dense than the cool air around it
• D. has stopped behaving like a gas

Q12. Every sip of home-prepared ORS tastes the same — not salty in one sip and sweet in another. Chapter 9 explains this is because sugar and salt in water form

• A. a non-uniform mixture
• B. a uniform mixture
• C. a saturated solution at room temperature
• D. a suspension of crystals

Q13. Before placing a stone on a digital weighing balance to find its mass, a Class 8 student places an empty watch glass on the pan and presses the tare button. Why?

• A. To increase the balance's accuracy permanently
• B. To set the reading to zero so that only the stone's mass is measured
• C. To convert grams into kilograms
• D. To switch the balance to volume mode

Q14. In Activity 9.2, baking soda is dissolved in water at 20 °C, then at 50 °C, and finally at 70 °C. The amount of baking soda that dissolves is greatest at

• A. 20 °C
• B. 50 °C
• C. 70 °C
• D. the same at all three temperatures

Q15. The amount of solute present in a fixed quantity of solution (or solvent) is called its

• A. concentration
• B. solubility
• C. density
• D. saturation