Hard

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

15 questions 18 min PYQ-grade reasoning

Q1. Consider the following statements about mixtures described in Chapter 9: I. A mixture of sand and water is non-uniform. II. A mixture of sugar and water is uniform. III. The presence of different gases in the atmosphere is a non-uniform mixture. Which statements are correct?
- A. I and II only
- B. II and III only
- C. I and III only
- D. All three
Q2. Assertion (A): 'Dilute' and 'concentrated' are relative terms, while 'saturated' is an absolute term at a given temperature. Reason (R): A saturated solution at a particular temperature contains the maximum solute that can dissolve, whereas dilute/concentrated only compare two solutions.
- A. Both A and R are true, and R is the correct explanation of A.
- B. Both A and R are true, but R is NOT the correct explanation of A.
- C. A is true, R is false.
- D. A is false, R is true.
Q3. Asha prepares a saturated solution of sugar in water at 25 °C. She then heats the solution to 60 °C without adding more water. The solution now is best described as
- A. still saturated at 60 °C
- B. a concentrated suspension
- C. behaving as a non-uniform mixture
- D. behaving as unsaturated at 60 °C
Q4. Question 1(i) in 'Keep the curiosity alive' asks whether the statement 'Oxygen gas is more soluble in hot water rather than in cold water' is true. The correct response based on Chapter 9 is
- A. True, because solubility of all substances rises with temperature.
- B. True, because warm water can hold more dissolved gas.
- C. False, because solubility of gases generally decreases with rise in temperature.
- D. False, because oxygen does not dissolve in water at all.
Q5. From Question 5 of 'Keep the curiosity alive', which one of the following is the most appropriate statement about a saturated solution at a given temperature?
- A. A saturated solution can still dissolve more solute.
- B. An unsaturated solution has dissolved the maximum amount of solute possible.
- C. No more solute can be dissolved into the saturated solution at that temperature.
- D. A saturated solution forms only at high temperatures.
Q6. An aluminium block has a mass of 27 g and a volume of 10 cm³. Based on the example in Chapter 9, the relative density of aluminium with respect to water is
- A. 27
- B. 10
- C. 2.7
- D. 0.37
Q7. A wooden stick and an iron rod are of the same size, yet the iron rod feels much heavier. The property of iron and wood that explains this difference, as discussed in Chapter 9, is
- A. solubility
- B. concentration
- C. density
- D. saturation
Q8. Consider the following inferences a student writes after performing Activity 9.2 with baking soda and water: I. Water at 70 °C dissolves more baking soda than water at 50 °C. II. For most substances, the solubility of a solid increases with an increase in temperature. III. A saturated solution at a particular temperature behaves as an unsaturated solution if the temperature is increased. Which of the inferences are supported by the activity?
- A. I and II only
- B. II and III only
- C. I and III only
- D. All three
Q9. Reema has a piece of modelling clay of mass 120 g moulded as a cube of volume 60 cm³. She then flattens it into a thin sheet without removing any clay. Compared to the cube, the density of the sheet will
- A. double, because the surface area has increased
- B. halve, because the cube has been flattened
- C. remain the same, because both mass and volume are unchanged
- D. become zero, because the shape is no longer compact
Q10. A village pond in summer becomes very warm. The most likely effect on the dissolved oxygen and fishes is
- A. Dissolved oxygen increases, helping fishes breathe better.
- B. Dissolved oxygen turns the pond into a saturated solution.
- C. Dissolved oxygen is unaffected because oxygen is a gas.
- D. Dissolved oxygen decreases, making it harder for fishes to breathe.
Q11. Consider the following statements based on the 'Ever heard of…' box about ice and water: I. The density of water is highest at 4 °C. II. When water freezes to ice at 0 °C, its volume increases. III. Because the same mass of ice occupies a larger volume than water, ice becomes lighter and floats. Which statements are correct?
- A. I and II only
- B. II and III only
- C. I and III only
- D. All three
Q12. Assertion (A): The density of most substances decreases on heating. Reason (R): On heating, the mass of the substance increases while the volume stays the same.
- A. Both A and R are true, and R is the correct explanation of A.
- B. Both A and R are true, but R is NOT the correct explanation of A.
- C. A is true, R is false.
- D. A is false, R is true.
Q13. Look at Fig. 9.7 in Chapter 9 for Activity 9.2 (dissolution of baking soda). Which of the following sets of items is part of the apparatus shown?
- A. Glass rod, beaker, wire gauze, tripod stand, spirit lamp, laboratory thermometer
- B. Test tube, retort stand, Bunsen burner, conical flask, glass funnel, filter paper
- C. Measuring cylinder, watch glass, digital balance, butter paper, dropper, tongs
- D. Beaker, magnifying lens, magnet, iron filings, sulfur powder, china dish
Q14. Consider how to choose the best measuring cylinder for measuring 70 mL of water. The best choice is the
- A. 50 mL measuring cylinder
- B. 100 mL measuring cylinder
- C. 250 mL measuring cylinder
- D. 500 mL measuring cylinder
Q15. Consider the following statements about density as discussed in Chapter 9: I. The density of a substance is independent of its shape or size. II. The density of a substance depends on its temperature and pressure. III. The density of a substance increases as its volume increases at fixed mass. Which statements are correct?
- A. I and II only
- B. II and III only
- C. I and III only
- D. All three

Your score and per-question explanations appear here instantly.