Chemistry CDS PYQ Topic Wise (2016–2026)

Explore: All CDS topics · CDS General Knowledge PYQs · CDS hub · Syllabus & pattern · CDS 2026

Answer first

Chemistry PYQs (previous year questions) for CDS: Chemistry (General Knowledge) had 212 questions across the 66 official CDS papers we tagged (2016–2026), and appeared in 22 of them. Asked in 11 of 11 years. The concepts asked in the most papers: Acids and Bases, Chemical Reactions, Atomic Structure.

Year-wise question count

Asked in 11 of 11 years, with 2 papers each year.

Most-asked concepts

Sorted by the number of papers a concept appeared in.

How to practise Chemistry PYQs

1. Start with the concepts at the top of the table. They have come back the most.
2. Solve one year’s Chemistry questions from the official PDF against the clock, then check the answer listed below.
3. Log every miss as a concept gap, a calculation slip or a misread. Each needs a different fix.
4. Once a concept is clean in two papers, move to the next. Then sit a full paper from the year pages.

Questions by year

Each line gives the question number and paper, type, concept, our one-line summary and the official answer, with a link to the official PDF.

CDS2026

• Q.21 (CDS (I) GK) · MCQ · Periodic Table: Match element symbols with their element groups PDF
• Q.22 (CDS (I) GK) · MCQ · Matter and Mixtures: Statements on elements, compounds and mixtures PDF
• Q.23 (CDS (I) GK) · MCQ · Chemistry in Daily Life: Statements on H₂SO₄, soap and nickel catalyst PDF
• Q.24 (CDS (I) GK) · MCQ · Atomic Structure: Mismatched pair of element and property PDF
• Q.25 (CDS (I) GK) · MCQ · Chemistry in Daily Life: Statements on nitrogen packing, tooth decay and metal reactivity PDF
• Q.26 (CDS (I) GK) · MCQ · Common Compounds: Mismatched pair of compound and chemical formula PDF
• Q.27 (CDS (I) GK) · MCQ · Water Hardness: Statements on temporary and permanent hardness of water PDF
• Q.28 (CDS (I) GK) · MCQ · Soaps and Detergents: Incorrect statement about soap micelles PDF
• Q.29 (CDS (I) GK) · MCQ · Acids and Bases: Statements on bases and alkalis PDF
• Q.30 (CDS (I) GK) · MCQ · Periodic Table: Statements on trends in the modern periodic table PDF
• Q.66 (CDS (II) GK) · MCQ · Common Compounds: Which substances are forms of calcium carbonate PDF
• Q.67 (CDS (II) GK) · MCQ · Chemical Reactions: Compound formed when HCl reacts with copper oxide PDF
• Q.68 (CDS (II) GK) · MCQ · Acids and Bases: Match natural sources with the acids they contain PDF
• Q.69 (CDS (II) GK) · MCQ · Common Compounds: Chemical formula of cooking soda PDF
• Q.70 (CDS (II) GK) · MCQ · Metals: Why sodium is stored under kerosene PDF
• Q.71 (CDS (II) GK) · MCQ · Solutions: Units in which solution concentration is expressed PDF
• Q.72 (CDS (II) GK) · MCQ · Electrolysis: Product of electrolysis of aqueous sodium chloride PDF
• Q.73 (CDS (II) GK) · MCQ · Mole Concept: Name for the mass of one mole of a substance PDF
• Q.74 (CDS (II) GK) · MCQ · Acids and Bases: Why an aqueous acid conducts electricity PDF
• Q.75 (CDS (II) GK) · MCQ · Acids and Bases: Name for a chemical that donates a proton PDF

CDS2025

• Q.51 (CDS (I) GK) · MCQ · Atomic Structure: Property shared by isobars PDF
• Q.52 (CDS (I) GK) · MCQ · Atomic Structure: What Rutherford's nuclear model could not explain PDF
• Q.53 (CDS (I) GK) · MCQ · Periodic Table: Name, symbol and valency of element with atomic number 11 PDF
• Q.54 (CDS (I) GK) · MCQ · Gases: Gas used in making soft drinks PDF
• Q.55 (CDS (I) GK) · MCQ · Elements and Compounds: Which substance is a compound PDF
• Q.56 (CDS (I) GK) · MCQ · Atomic Structure: Discovery from Rutherford's gold foil experiment PDF
• Q.57 (CDS (I) GK) · MCQ · Periodic Table: Identify a metalloid PDF
• Q.58 (CDS (I) GK) · MCQ · Atomic Structure: What Dalton's atomic theory does not explain PDF
• Q.59 (CDS (I) GK) · MCQ · Acids and Bases: Set containing only Lewis acids PDF
• Q.60 (CDS (I) GK) · MCQ · Atomic Structure: Number of electrons in given ionic species PDF
• Q.31 (CDS (II) GK) · MCQ · Metallurgy: Metal extracted by electrolysis of its molten compound (official answer: D) PDF
• Q.32 (CDS (II) GK) · MCQ · Allotropes of Carbon: Property that graphene does not have (official answer: D) PDF
• Q.33 (CDS (II) GK) · MCQ · Polymers: Why plastics do not degrade easily (official answer: B) PDF
• Q.34 (CDS (II) GK) · MCQ · Organic Compounds: General formula of a carboxylic acid (official answer: C) PDF
• Q.35 (CDS (II) GK) · MCQ · Organic Compounds: Incorrect statement about benzene (official answer: D) PDF
• Q.36 (CDS (II) GK) · MCQ · Fertilizers: Which is not a nitrogen fertilizer (official answer: C) PDF
• Q.37 (CDS (II) GK) · MCQ · Periodic Table: Electronic configuration of a transition metal (official answer: D) PDF
• Q.38 (CDS (II) GK) · MCQ · Oxidation State: Elements that show variable oxidation numbers (official answer: C) PDF
• Q.39 (CDS (II) GK) · MCQ · Gases: Gas that smells like rotten eggs (official answer: B) PDF
• Q.40 (CDS (II) GK) · MCQ · Chemical Reactions: Type of reaction between potassium sulphate and barium chloride (official answer: D) PDF
• Q.50 (CDS (II) GK) · MCQ · Acids and Bases: Nature of a solution with pH below 7 (official answer: C) PDF

CDS2024

• Q.25 (CDS (I) GK) · MCQ · Plastics: Why plastics cause environmental problems (official answer: A) PDF
• Q.33 (CDS (I) GK) · MCQ · Oxides: Identify the oxide of a given type among metal and non-metal oxides (official answer: D) PDF
• Q.34 (CDS (I) GK) · MCQ · Hydrocarbons: Order of octane number of butane, pentane, hexane and cyclohexane (official answer: C) PDF
• Q.35 (CDS (I) GK) · MCQ · Reactivity Series: Order of reactivity of Mg, Al, Zn and Fe (official answer: A) PDF
• Q.36 (CDS (I) GK) · MCQ · Organic Compounds: Why methanol is toxic to humans (official answer: B) PDF
• Q.37 (CDS (I) GK) · MCQ · Organic Compounds: Composition of vinegar (official answer: A) PDF
• Q.39 (CDS (I) GK) · MCQ · Hydrocarbons: Identify the odd one among long-chain alkanes (official answer: A) PDF
• Q.55 (CDS (I) GK) · MCQ · Chemical Compounds: Identify which listed compound is not of a given type (official answer: dropped in the final key) PDF
• Q.77 (CDS (I) GK) · MCQ · Periodic Table: Order of atomic radius of Li, Na, Be and O (official answer: A) PDF
• Q.78 (CDS (I) GK) · MCQ · Organic Reactions: Catalyst used to hydrogenate unsaturated hydrocarbons (official answer: D) PDF
• Q.79 (CDS (I) GK) · MCQ · Chemical Bonding: Compound with the highest ionic character (official answer: D) PDF
• Q.8 (CDS (II) GK) · MCQ · Solutions: Medium in which a given substance behaves in a stated way PDF
• Q.11 (CDS (II) GK) · MCQ · Colloids: Colloid whose dispersing medium is a liquid PDF
• Q.12 (CDS (II) GK) · MCQ · Isotopes: The two isotopes of chlorine PDF
• Q.13 (CDS (II) GK) · MCQ · Metals: Metal that is not stored under oil PDF
• Q.14 (CDS (II) GK) · MCQ · Chemical Compounds: Use for which potassium nitrate is not employed PDF
• Q.15 (CDS (II) GK) · MCQ · Cement and Concrete: Why fresh concrete is covered with wet gunny bags PDF
• Q.16 (CDS (II) GK) · MCQ · Gases: Incorrect statement on uses and isotopes of common gases PDF
• Q.17 (CDS (II) GK) · Matching · Chemical Compounds: Match trade names like baking soda with chemical names PDF
• Q.18 (CDS (II) GK) · MCQ · Glass: Statement on glass that is not true PDF
• Q.19 (CDS (II) GK) · MCQ · Atomic Structure: Particle that decides chemical properties of an element PDF
• Q.20 (CDS (II) GK) · MCQ · Chemical Compounds: Substance used to bleach paper PDF

CDS2023

• Q.11 (CDS (I) GK) · MCQ · Chemical Reactions: Statements on burning a magnesium ribbon in air (official answer: D) PDF
• Q.12 (CDS (I) GK) · MCQ · Chemical Reactions: Statements on quicklime reacting with water (official answer: B) PDF
• Q.13 (CDS (I) GK) · MCQ · Chemical Reactions: Statements on heating lead nitrate powder (official answer: D) PDF
• Q.14 (CDS (I) GK) · MCQ · Oxidation and Reduction: Process that is not an oxidation reaction (official answer: B) PDF
• Q.49 (CDS (I) GK) · MCQ · Acids and Bases: Composition of a soda-acid fire extinguisher (official answer: A) PDF
• Q.50 (CDS (I) GK) · MCQ · Acids and Bases: Statements on safely diluting concentrated nitric acid (official answer: C) PDF
• Q.51 (CDS (I) GK) · MCQ · Acids and Bases: Correct pH order of common substances (official answer: D) PDF
• Q.52 (CDS (I) GK) · MCQ · Metals: Incorrect statement about anodizing (official answer: C) PDF
• Q.53 (CDS (I) GK) · MCQ · Carbon and Compounds: Why naphthalene burns with a sooty yellow flame (official answer: B) PDF
• Q.54 (CDS (I) GK) · MCQ · Metals: Statements on the reaction of Fe2O3 with aluminium (official answer: A) PDF
• Q.6 (CDS (II) GK) · MCQ · Elements: Chemical symbols of gold, tin and lead (official answer: C) PDF
• Q.8 (CDS (II) GK) · MCQ · Water Hardness: Method used to remove hardness of water (official answer: A) PDF
• Q.9 (CDS (II) GK) · MCQ · Chemical Reactions: Reaction of slaked lime with CO2 during whitewashing (official answer: D) PDF
• Q.10 (CDS (II) GK) · MCQ · Chemical Equations: Balanced equation for iron reacting with steam (official answer: C) PDF
• Q.39 (CDS (II) GK) · MCQ · Physical and Chemical Changes: Case involving both physical and chemical change (official answer: A) PDF
• Q.40 (CDS (II) GK) · MCQ · Allotropes of Carbon: Correct statement about diamond and graphite (official answer: B) PDF
• Q.41 (CDS (II) GK) · MCQ · Matter: Which substance is a compound (official answer: A) PDF
• Q.42 (CDS (II) GK) · MCQ · Elements: Number of naturally occurring elements (official answer: B) PDF
• Q.43 (CDS (II) GK) · MCQ · Acids and Bases: Incorrect statement about acids in common substances (official answer: C) PDF

CDS2022

• Q.7 (CDS (I) GK) · MCQ · Chemical Reactions: Moles of oxygen to burn one mole of glucose (official answer: C) PDF
• Q.8 (CDS (I) GK) · MCQ · Chemical Reactions: Which change is not an oxidation reaction (official answer: B) PDF
• Q.9 (CDS (I) GK) · MCQ · Acids and Bases: Where methanoic acid is normally found (official answer: C) PDF
• Q.10 (CDS (I) GK) · MCQ · Mole Concept: Number of moles in a given mass of helium (official answer: B) PDF
• Q.11 (CDS (I) GK) · MCQ · Carbon and its Compounds: Meaning of a sooty yellow flame from fuel (official answer: B) PDF
• Q.12 (CDS (I) GK) · MCQ · Carbon and its Compounds: Saturated and unsaturated bonds in cyclohexane (official answer: C) PDF
• Q.13 (CDS (I) GK) · MCQ · Metals and Non-metals: What non-metal oxides form in water (official answer: B) PDF
• Q.27 (CDS (I) GK) · MCQ · Environmental Chemistry: Main cause of acid rain (official answer: A) PDF
• Q.11 (CDS (II) GK) · MCQ · Acids and Bases: Fluid injected by nettle leaf hairs (official answer: A) PDF
• Q.12 (CDS (II) GK) · MCQ · Acids and Bases: Nature of milk of magnesia (official answer: B) PDF
• Q.14 (CDS (II) GK) · MCQ · Metals and Non-metals: Property of metals used in school bells (official answer: B) PDF
• Q.15 (CDS (II) GK) · MCQ · Chemistry in Everyday Life: Statements about tincture of iodine (official answer: C) PDF
• Q.16 (CDS (II) GK) · MCQ · Atomic Structure: Ion not isoelectronic with chloride (official answer: B) PDF
• Q.61 (CDS (II) GK) · MCQ · Chemistry in Everyday Life: Metal salt given before abdominal X-ray (official answer: A) PDF
• Q.62 (CDS (II) GK) · MCQ · Chemistry in Everyday Life: Substance used to store biological tissues (official answer: A) PDF
• Q.63 (CDS (II) GK) · MCQ · Chemical Reactions: Metal reacting with iron oxide in thermite welding (official answer: A) PDF

CDS2021

• Q.97 (CDS (I) GK) · MCQ · Chemical Reactions: Brown gas evolved on heating lead nitrate (official answer: D) PDF
• Q.98 (CDS (I) GK) · MCQ · Chemical Reactions: Substance that tarnishes silver articles (official answer: A) PDF
• Q.99 (CDS (I) GK) · MCQ · Metals and Non-metals: Metal stored under kerosene (official answer: B) PDF
• Q.100 (CDS (I) GK) · MCQ · Solutions: Mass by mass percentage of a given solution (official answer: C) PDF
• Q.101 (CDS (I) GK) · MCQ · Metals and Non-metals: Non-metal that is lustrous (official answer: D) PDF
• Q.102 (CDS (I) GK) · MCQ · Metals and Non-metals: Metal that is both malleable and ductile (official answer: B) PDF
• Q.113 (CDS (I) GK) · MCQ · Acids and Bases: Acid found abundantly in tomato (official answer: C) PDF
• Q.114 (CDS (I) GK) · MCQ · Acids and Bases: Compound used in soda-acid fire extinguishers (official answer: B) PDF
• Q.115 (CDS (I) GK) · MCQ · Chemistry in Everyday Life: Sodium compound used to soften hard water (official answer: A) PDF
• Q.116 (CDS (I) GK) · MCQ · Chemical Reactions: Reaction of slaked lime used for whitewashing (official answer: D) PDF
• Q.7 (CDS (II) GK) · MCQ · Acids and Bases: Statements about universal indicator (official answer: D) PDF
• Q.8 (CDS (II) GK) · MCQ · Carbon and its Compounds: Carbon allotropes that conduct electricity (official answer: C) PDF
• Q.9 (CDS (II) GK) · MCQ · Carbon and its Compounds: Approximate percentage of carbon in Earth's crust (official answer: B) PDF
• Q.10 (CDS (II) GK) · MCQ · Chemical Reactions: Green coating formed on copper in moist air (official answer: A) PDF
• Q.11 (CDS (II) GK) · MCQ · Metallurgy: Process converting sulphide ores to oxides (official answer: B) PDF
• Q.12 (CDS (II) GK) · MCQ · Alloys: Constituents of solder (official answer: B) PDF
• Q.23 (CDS (II) GK) · MCQ · Metals and Non-metals: Reactivity order of metals with dilute acid (official answer: A) PDF
• Q.24 (CDS (II) GK) · MCQ · Acids and Bases: Acid in nettle leaf stings (official answer: A) PDF
• Q.25 (CDS (II) GK) · MCQ · Acids and Bases: Statements about bases and alkalis (official answer: C) PDF
• Q.26 (CDS (II) GK) · MCQ · Laboratory Chemistry: Material in a guard tube when preparing HCl gas (official answer: A) PDF

CDS2020

• Q.1 (CDS (I) GK) · MCQ · Atomic Structure: What alpha-particle scattering by gold foil reveals (official answer: C) PDF
• Q.2 (CDS (I) GK) · MCQ · Atomic Structure: Pair of elements that are isobars (official answer: D) PDF
• Q.3 (CDS (I) GK) · MCQ · Chemical Reactions: Displacement reaction that cannot occur (official answer: C) PDF
• Q.4 (CDS (I) GK) · MCQ · Acids and Bases: Name for a solution with pH zero (official answer: B) PDF
• Q.6 (CDS (I) GK) · MCQ · Acids and Bases: Match compounds with their uses (official answer: A) PDF
• Q.17 (CDS (I) GK) · MCQ · Chemical Reactions: Gas that turns limewater milky (official answer: C) PDF
• Q.21 (CDS (I) GK) · MCQ · Common Compounds: Match common compounds with formulae (official answer: A) PDF
• Q.22 (CDS (I) GK) · MCQ · Common Compounds: Water molecules in hydrated copper sulphate (official answer: C) PDF
• Q.23 (CDS (I) GK) · MCQ · Chemical Reactions: Why silver articles turn black in air (official answer: C) PDF
• Q.96 (CDS (II) GK) · MCQ · Separation Techniques: Method to separate salt and ammonium chloride (official answer: A) PDF
• Q.97 (CDS (II) GK) · MCQ · History of Chemistry: Scientist who introduced element symbols (official answer: C) PDF
• Q.98 (CDS (II) GK) · MCQ · Elements: Pair of elements liquid at room temperature (official answer: D) PDF
• Q.99 (CDS (II) GK) · MCQ · Oxides: Oxide that is both acidic and basic (official answer: A) PDF
• Q.100 (CDS (II) GK) · MCQ · Chemical Reactions: Compound that blackens silver in air (official answer: D) PDF
• Q.111 (CDS (II) GK) · MCQ · Isotopes: Radioactive isotope of hydrogen (official answer: C) PDF
• Q.112 (CDS (II) GK) · MCQ · Common Compounds: Substance used to store biological tissues (official answer: A) PDF
• Q.113 (CDS (II) GK) · MCQ · Metals: Metal that does not form an oxide with oxygen (official answer: D) PDF
• Q.114 (CDS (II) GK) · MCQ · Valency: Valencies of phosphorus (official answer: D) PDF
• Q.115 (CDS (II) GK) · MCQ · Chemical Reactions: Products of heating lead nitrate (official answer: B) PDF

CDS2019

• Q.51 (CDS (I) GK) · MCQ · Molecular Shapes: Match molecules with their shapes (official answer: B) PDF
• Q.52 (CDS (I) GK) · MCQ · Separation Techniques: Method to separate tiny insoluble particles from a liquid (official answer: C) PDF
• Q.53 (CDS (I) GK) · MCQ · Organic Analysis: Element not detected by Lassaigne's test (official answer: D) PDF
• Q.54 (CDS (I) GK) · MCQ · Isomerism: Compound class without functional group isomerism (official answer: C) PDF
• Q.55 (CDS (I) GK) · MCQ · Conformations: Incorrect statement on ethane conformations (official answer: C) PDF
• Q.56 (CDS (I) GK) · MCQ · Polymers: Monomer used to make Nylon 6 (official answer: B) PDF
• Q.78 (CDS (I) GK) · MCQ · Polymers: Plastic type of a bottle that resists hot water (official answer: D) PDF
• Q.79 (CDS (I) GK) · MCQ · Thermodynamics: Which quantities are state functions (official answer: A) PDF
• Q.80 (CDS (I) GK) · MCQ · Thermodynamics: Temperature at which a reaction becomes spontaneous (official answer: C) PDF
• Q.81 (CDS (I) GK) · MCQ · Hybridisation: Hybridisation of the central atom in PCl5 (official answer: D) PDF
• Q.92 (CDS (II) GK) · MCQ · States of Matter: Statements on particles of matter (official answer: C) PDF
• Q.95 (CDS (II) GK) · MCQ · Mixtures: Statements on separating mixtures (official answer: B) PDF
• Q.96 (CDS (II) GK) · MCQ · Atomic Structure: Incorrect statement on atoms (official answer: B) PDF
• Q.112 (CDS (II) GK) · MCQ · Elements: Element that is monatomic (official answer: D) PDF
• Q.113 (CDS (II) GK) · MCQ · Allotropes: Bonding of carbon atoms in graphite (official answer: B) PDF
• Q.114 (CDS (II) GK) · MCQ · Colloids: Why soap solution looks cloudy (official answer: B) PDF
• Q.116 (CDS (II) GK) · MCQ · Separation Techniques: What chromatography cannot separate (official answer: A) PDF
• Q.117 (CDS (II) GK) · MCQ · Periodic Table: Scientist who said atomic number is more basic than mass (official answer: B) PDF

CDS2018

• Q.1 (CDS (I) GK) · MCQ · Elements and Uses: Element used as timekeeper in atomic clocks (official answer: B) PDF
• Q.3 (CDS (I) GK) · MCQ · Acids and Bases: Gas that dissolves in water to give an acidic solution (official answer: A) PDF
• Q.5 (CDS (I) GK) · MCQ · Chemical Equations: Balancing coefficients in reduction of Fe2O3 by CO (official answer: B) PDF
• Q.6 (CDS (I) GK) · MCQ · Noble Gases: Why argon is filled in tungsten filament bulbs (official answer: A) PDF
• Q.28 (CDS (I) GK) · MCQ · Noble Gases: Noble gas responsible for brightness of a flashgun (official answer: B) PDF
• Q.29 (CDS (I) GK) · MCQ · Matter and Compounds: Feature that is not a characteristic of a compound (official answer: A) PDF
• Q.30 (CDS (I) GK) · MCQ · Water Hardness: Salts that cause temporary hardness of water (official answer: D) PDF
• Q.31 (CDS (I) GK) · MCQ · Atomic Structure: Identify an isobar of calcium from proton/neutron counts (official answer: D) PDF
• Q.1 (CDS (II) GK) · MCQ · Chemical Reactions: Reactants that give a gas turning limewater milky (official answer: B) PDF
• Q.2 (CDS (II) GK) · MCQ · Mole Concept: Moles of CO from partial oxidation of methane (official answer: A) PDF
• Q.3 (CDS (II) GK) · MCQ · Chemical Reactions: Pair of reactants that produces hydrogen gas (official answer: A) PDF
• Q.4 (CDS (II) GK) · MCQ · Properties of Gases: Property common to H2, N2, O2 and CO2 (official answer: B) PDF
• Q.5 (CDS (II) GK) · MCQ · Molecular Formula: Atom count and mass ratios in a compound C7H7NO2 (official answer: dropped in the final key) PDF
• Q.6 (CDS (II) GK) · MCQ · Hydrocarbons: General formula of saturated hydrocarbons (official answer: A) PDF
• Q.24 (CDS (II) GK) · MCQ · Equivalent Weight: Equivalent weight of barium hydroxide (official answer: A) PDF
• Q.25 (CDS (II) GK) · MCQ · Oxidation State: Nitrogen oxide with highest oxidation state of nitrogen (official answer: D) PDF
• Q.26 (CDS (II) GK) · MCQ · Allotropes of Carbon: Statement not true for diamond (official answer: C) PDF
• Q.27 (CDS (II) GK) · MCQ · Chemical Reactions: Reaction giving most hydrogen per gram of compound (official answer: A) PDF

CDS2017

• Q.13 (CDS (I) GK) · MCQ · Physical and Chemical Changes: Example of a physical change (official answer: C) PDF
• Q.14 (CDS (I) GK) · MCQ · Acids and Bases: pH of multiple-distilled water (official answer: D) PDF
• Q.15 (CDS (I) GK) · MCQ · Periodic Table: Most characteristic property of an element (official answer: D) PDF
• Q.16 (CDS (I) GK) · MCQ · Atomic Structure: Term for calcium and argon with mass 40 (official answer: C) PDF
• Q.17 (CDS (I) GK) · MCQ · Atomic Structure: Scientist who proposed the plum pudding model (official answer: D) PDF
• Q.18 (CDS (I) GK) · MCQ · Mole Concept: Number of atoms in 46 g of sodium (official answer: C) PDF
• Q.41 (CDS (I) GK) · MCQ · States of Matter: Maximum number of states of matter (official answer: C) PDF
• Q.42 (CDS (I) GK) · MCQ · Atomic Structure: What chemical properties of an element depend on (official answer: D) PDF
• Q.44 (CDS (I) GK) · MCQ · Solutions: Normality of a sulphuric acid solution (official answer: B) PDF
• Q.6 (CDS (II) GK) · MCQ · Water Pollution: Contaminant behind blue baby syndrome (official answer: C) PDF
• Q.17 (CDS (II) GK) · MCQ · Acids and Bases: Role of water reacting with hydrogen sulphate ion (official answer: B) PDF
• Q.18 (CDS (II) GK) · MCQ · Mole Concept: Hydrogen atoms in 1.5 g of glucose (official answer: D) PDF
• Q.19 (CDS (II) GK) · MCQ · Chemistry in Daily Life: White material used to set fractured bones (official answer: B) PDF
• Q.20 (CDS (II) GK) · MCQ · Glass: Glass type used for optical instruments (official answer: D) PDF
• Q.22 (CDS (II) GK) · MCQ · Fuels: Main constituents of biogas (official answer: B) PDF
• Q.54 (CDS (II) GK) · MCQ · Colloids: What an emulsion consists of (official answer: C) PDF
• Q.55 (CDS (II) GK) · MCQ · Radioactivity: Radioactive substance entering via food chain (official answer: D) PDF
• Q.61 (CDS (II) GK) · MCQ · Biochemistry: Source of foul smell of spilled urine (official answer: D) PDF
• Q.62 (CDS (II) GK) · MCQ · Solutions: Pressure applied in reverse osmosis (official answer: A) PDF
• Q.63 (CDS (II) GK) · MCQ · Polymers: Polymer without glucose units (official answer: D) PDF
• Q.64 (CDS (II) GK) · MCQ · Chemistry in Daily Life: What tincture of iodine does not contain (official answer: B) PDF

CDS2016

• Q.9 (CDS (I) GK) · MCQ · Polymers: First man-made plastic used for cooker handles (official answer: D) PDF
• Q.10 (CDS (I) GK) · MCQ · Industrial Chemicals: Product made using methyl isocyanate at Bhopal (official answer: D) PDF
• Q.15 (CDS (I) GK) · MCQ · Alloys: Why German silver is so named (official answer: C) PDF
• Q.26 (CDS (I) GK) · MCQ · Bioinorganic Chemistry: Metal ion in vitamin B12 (official answer: C) PDF
• Q.37 (CDS (I) GK) · MCQ · Physical and Chemical Changes: Example of a chemical change (official answer: A) PDF
• Q.42 (CDS (I) GK) · MCQ · Environmental Chemistry: Statements on acid rain and eutrophication (official answer: A) PDF
• Q.44 (CDS (I) GK) · MCQ · Chemical Properties: Incorrect statement involving an explosive mixture (official answer: C) PDF
• Q.45 (CDS (I) GK) · MCQ · Atomic Structure: Incorrect statement on isotopes and isobars (official answer: D) PDF
• Q.1 (CDS (II) GK) · MCQ · Environmental Chemistry: Gas released mostly from urban landfills (official answer: C) PDF
• Q.5 (CDS (II) GK) · MCQ · Air Pollution: Pollutant that binds haemoglobin (official answer: C) PDF
• Q.7 (CDS (II) GK) · MCQ · Carbon and Compounds: Which is not an allotrope of carbon (official answer: A) PDF
• Q.8 (CDS (II) GK) · MCQ · Industrial Chemistry: Chemical used to degum raw material for paper (official answer: C) PDF
• Q.9 (CDS (II) GK) · MCQ · Soil Chemistry: Purpose of applying dolomite to farmland (official answer: A) PDF
• Q.11 (CDS (II) GK) · MCQ · Environmental Chemistry: Fertilizer causing toxic substance in groundwater (official answer: A) PDF
• Q.12 (CDS (II) GK) · MCQ · Periodic Table: Element that does not form a solid hydrogen carbonate (official answer: D) PDF
• Q.26 (CDS (II) GK) · MCQ · Alkaline Earth Metals: Match Mg, Ca, Sr, Ba with uses (official answer: C) PDF
• Q.27 (CDS (II) GK) · MCQ · Oxidation Number: Oxidation states of hydrogen (official answer: D) PDF
• Q.28 (CDS (II) GK) · MCQ · Electrochemistry: Electrode potential of standard hydrogen electrode (official answer: A) PDF

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FAQ

How many Chemistry questions come in CDS?

In the official papers we tagged: 20 in 2026, 21 in 2025, 22 in 2024, 19 in 2023, 16 in 2022, 20 in 2021, 19 in 2020, 18 in 2019, 18 in 2018, 21 in 2017 and 18 in 2016 (2 papers each year). That is 212 questions in all, about 8% of General Knowledge.

Which Chemistry topics repeat in CDS?

Asked in the most papers: Acids and Bases, Chemical Reactions, Atomic Structure. The concept table lists every one with its count.

Are these official CDS questions?

Yes. Every question is from an official CDS paper hosted on our year pages. The one-line summaries are ours; open the PDF linked beside each question for the full text.