CBSE Class 9 Science Exploring Mixtures and Their Separation (Class 9 NCERT New) Quiz 8

1. Blood is neither a solution nor a true suspension. It is a colloid.

A True B False

2. Which of the following is an example of a colloid?

A Milk B Tomato sauce C Ice cream D All of the above

3. What are the main components of blood that are separated after blood donation?

A Plasma, platelets, white blood cells, red blood cells B Plasma, glucose, hormones, red blood cells C Platelets, enzymes, antibodies, plasma D Red blood cells, lymph, bile, platelets

4. Blood donation is unsafe and cannot be replaced naturally.

A True B False

5. What is the main difference between solutions, suspensions, and colloids in terms of particle size?

A Solutions have the smallest particles (less than 1 nm), colloids have larger particles (1–1000 nm), and suspensions have much larger particles (more than 1000 nm). B Solutions have the largest particles, colloids have medium-sized particles, and suspensions have the smallest particles. C Colloids have the smallest particles, suspensions have medium-sized particles, and solutions have the largest particles. D Suspensions have the smallest particles, solutions have medium-sized particles, and colloids have the largest particles.

6. Unlike suspension, the particles in a colloid do not settle over time from the mixture. They are uniformly dispersed throughout the mixture as in a solution. True or False: The particles in a colloid settle over time from the mixture.

A True B False

7. What is the Tyndall Effect?

A The Tyndall Effect is the scattering of light by particles in a mixture, making the path of light visible. B The Tyndall Effect is the absorption of light by a transparent material. C The Tyndall Effect is the reflection of light from a mirror surface. D The Tyndall Effect is the bending of light as it passes through a lens.

8. The Tyndall Effect is observed when light passes through a solution with very small particles and the path of light is not visible.

A True B False

9. Based on what you know about solutions, suspensions and colloids, what type of mixture do you think clouds are and why?

A Clouds are colloids because they consist of tiny water droplets dispersed in air. B Clouds are solutions because the water is completely dissolved in air. C Clouds are suspensions because the water droplets settle out over time. D Clouds are pure substances because they contain only water.

10. Cities with a lot of smoke and dust in the air often look hazy because:

A Smoke and dust scatter sunlight, making the air appear unclear. B The buildings are taller in such cities. C There is more water vapor in the air. D The temperature is always higher in these cities.