CBSE Class 9 Chemistry Chapter 2 Is Matter Around Us Pure — 20 MCQs with Answers

A pure substance has one type of particle and fixed properties throughout — distilled water, pure copper, and oxygen gas are classic examples. A mixture contains two or more pure substances physically combined, without fixed composition. Recognising the difference is the foundation of this chapter. CBSE questions often present everyday examples (milk, brass, air) and ask you to classify them. Additionally, understanding that mixtures retain the individual properties of their components helps you predict separation methods. For instance, iron filings in sand can be removed with a magnet because iron retains its magnetic property in the mixture. The four MCQs below test your grasp of definitions, classification, and reasoning about fixed versus variable composition.

Homogeneous mixtures appear uniform throughout — salt water, air, brass, and vinegar all look and behave the same in every part. Heterogeneous mixtures show visible differences — sand and iron filings, oil and water, and soil are obvious examples. The distinction is critical because it determines separation methods. Filtration works well for heterogeneous mixtures where particles are large enough to be trapped. In contrast, homogeneous mixtures require techniques like distillation or chromatography. CBSE exam papers often present a list of substances and ask you to pick the homogeneous or heterogeneous one, or to match a mixture to a suitable separation method. The four MCQs below will test your ability to classify mixtures at a glance and reason about uniformity versus visibility.

Solutions are true homogeneous mixtures where solute particles are dissolved at the molecular or ionic level; they do not settle, cannot be filtered, and are transparent. Suspensions are heterogeneous; solid particles remain visible, settle on standing, and can be filtered. Colloids lie in between: particles are small enough (1–1000 nm) that they do not settle quickly, yet large enough to scatter light (Tyndall effect). Milk, fog, and blood are colloids. CBSE questions frequently ask you to identify the type based on properties like settling, filterability, or the Tyndall effect. Below are four MCQs that test your understanding of these distinctions and your ability to apply the Tyndall test in real scenarios.

Separation methods exploit differences in physical properties — size, solubility, boiling point, or magnetism. Filtration separates insoluble solids from liquids using filter paper. Evaporation recovers dissolved solids by vaporising the solvent. Distillation separates liquids with different boiling points (like acetone and water). Chromatography separates coloured substances or mixtures based on differential movement on paper. Magnetic separation uses a magnet to remove magnetic materials like iron. CBSE exams expect you to match a mixture to the correct technique and justify your choice. The four MCQs below simulate typical board questions, requiring you to think through the nature of components and pick the most efficient separation method.

Physical changes alter the form or state of matter without changing its chemical identity — ice melting to water, sugar dissolving, wax melting. No new substance forms, and the change is often reversible. Chemical changes produce new substances with new properties — burning wood forms ash and gases, rusting iron forms iron oxide, curdling milk forms lactic acid. Energy is usually released or absorbed, and the change is irreversible under normal conditions. CBSE questions test your ability to classify everyday changes and justify whether a new substance has formed. The four MCQs below cover common examples and require reasoning about reversibility, energy change, and formation of new products.

Multiple-choice questions in CBSE Class 9 Chemistry carry one mark each and demand both speed and accuracy. Read the question carefully to identify the key concept being tested — is it asking for a definition, a classification, a separation method, or an application? Eliminate obviously wrong options first. If the question involves a list (for example, 'Which of these is a colloid?'), recall the defining property (Tyndall effect, particle size) and match each option against it. For assertion-reason questions, read both statements independently, decide if each is true, then check whether the reason correctly explains the assertion. Never spend more than 30–45 seconds on a single MCQ; if stuck, mark it for review and move on. In the final minutes, return to flagged questions with a fresh mind. Practice at least 50–60 MCQs before the exam to build pattern recognition and confidence. The NCERT exemplar and previous years' question papers from CBSE are excellent sources for additional MCQs beyond this page.

Students often confuse colloids with suspensions, mistakenly thinking both settle or both scatter light equally. Remember: suspensions settle quickly and have larger particles; colloids do not settle easily and show the Tyndall effect. Another frequent error is classifying any cloudy mixture as heterogeneous — milk looks uniform but is actually a colloid (homogeneous at macro level, heterogeneous at particle level). In separation-technique MCQs, students pick distillation for every liquid mixture without checking boiling points; distillation works only when components have different boiling points. For physical versus chemical change, many assume that if heat is involved, it must be chemical — but boiling water (physical) and burning wood (chemical) both involve heat, yet only burning forms new substances. Finally, in assertion-reason questions, do not assume that if both statements are true, the reason automatically explains the assertion — always verify the logical link. Avoiding these pitfalls will lift your score by 2–3 marks in a 20-mark MCQ section.

Mastering Chapter 2 Is Matter Around Us Pure requires more than memorising definitions — you need to apply concepts to new scenarios, interpret diagrams, and tackle tricky assertion-reason MCQs under time pressure. CBSETUTOR.ai gives your child a personal AI tutor available 24×7, ready to explain every MCQ in this chapter with step-by-step reasoning. Stuck on why milk shows the Tyndall effect but sugar solution does not? Snap a photo of the question, upload it, and receive an instant, NCERT-aligned explanation in simple language. The platform generates unlimited practice MCQs, tracks weak areas (for example, if your child repeatedly misses separation-technique questions, the AI highlights that), and adapts difficulty to match progress. Unlike static PDFs or YouTube videos, CBSETUTOR.ai responds to your child's specific doubts in real time, making revision efficient and confidence-building. Parents in metros and smaller towns alike trust CBSETUTOR.ai because it costs just ₹999 per month for all subjects across Classes 6–12 — one flat fee, no hidden charges, no per-subject upselling. Start with a free 3-day trial and watch your child move from confusion to clarity in Chapter 2 and beyond.