Try each question on your own first. Use the Show Answer button only after you have selected your option, then read the explanation and revise the related concept from your chapter notes.
1. Which of the following is considered a pure substance in chemistry?
A. Milk
B. Distilled water
C. Air
D. Fruit juice
Answer: B. Distilled water
Explanation: A pure substance consists of a single type of particle. Distilled water contains only H₂O molecules, whereas milk, air, and juice are mixtures.
2. A mixture of salt and water is an example of a:
A. Homogeneous mixture
B. Heterogeneous mixture
C. Compound
D. Suspension
Answer: A. Homogeneous mixture
Explanation: When salt dissolves completely in water, it forms a uniform composition throughout, making it a homogeneous mixture.
3. The scattering of a beam of light by colloidal particles is called:
A. Brownian motion
B. Tyndall effect
C. Reflection
D. Dispersion
Answer: B. Tyndall effect
Explanation: The Tyndall effect is the phenomenon in which colloidal particles scatter light passing through the mixture, making the path of light visible.
4. Which technique is used to separate butter from curd (or cream from milk)?
A. Evaporation
B. Centrifugation
C. Chromatography
D. Sublimation
Answer: B. Centrifugation
Explanation: Centrifugation works on the principle that denser particles are forced to the bottom and lighter particles stay at the top when spun rapidly.
5. Which of the following is a chemical change?
A. Melting of ice
B. Rusting of iron
C. Dissolving salt in water
D. Cutting a piece of wood
Answer: B. Rusting of iron
Explanation: Rusting creates a new chemical compound (iron oxide) with completely different chemical properties, making it a chemical change.
6. Tincture of iodine is a solution formed by dissolving iodine in:
A. Water
B. Alcohol
C. Acetone
D. Benzene
Answer: B. Alcohol
Explanation: Tincture of iodine, widely used as an antiseptic, has iodine (solid) as the solute and alcohol (liquid) as the solvent.
7. Brass is an alloy made up of which two metals?
A. Copper and Zinc
B. Copper and Tin
C. Iron and Carbon
D. Aluminum and Copper
Answer: A. Copper and Zinc
Explanation: Brass is a solid-in-solid homogeneous mixture (alloy) containing approximately 70% Copper and 30% Zinc.
8. Which of the following is an example of a suspension?
A. Salt solution
B. Chalk powder in water
C. Milk
D. Air
Answer: B. Chalk powder in water
Explanation: Chalk powder in water is a heterogeneous mixture where solute particles do not dissolve and remain suspended visible to the naked eye.
9. Two immiscible liquids having different densities can be separated using a:
A. Filter paper
B. Separating funnel
C. Fractional distillation column
D. Centrifuge
Answer: B. Separating funnel
Explanation: A separating funnel separates immiscible liquids (like oil and water) into distinct layers based on their densities.
10. What is the mass percentage of a solution containing 40 g of salt in 320 g of water?
A. 10%
B. 11.1%
C. 12.5%
D. 15%
Answer: B. 11.1%
Explanation: Mass of solution = 40g + 320g = 360g. Mass percentage = (40 / 360) × 100 = 11.11%.
This page contains a chapter-wise objective practice set. Try the questions without checking the answer first, then use the explanation to understand the point you missed. The current page contains 10 questions, so you can practise in smaller sets when you are revising.
Quick revision tip
After the practice set, write down the question numbers you missed and revise only those concepts once more. This makes MCQ practice more useful than repeatedly attempting the same questions without reviewing mistakes.
