Organic Chemistry Polymers Competitive Exams
100 questions · General Science
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Question 1 of 100
Plastic waste is a serious environmental problem mainly because it is
ExplanationIt persists in the environment for hundreds of years.
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Question 2 of 100
Thermoplastics
ExplanationPolythene and PVC are thermoplastics.
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Question 3 of 100
The chemical formula of methane is
ExplanationOne carbon bonded to four hydrogens.
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Question 4 of 100
The functional group –NH₂ is present in
ExplanationMethylamine (CH₃NH₂) is a simple example; amino acids contain both –NH₂ and –COOH.
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Question 5 of 100
Markovnikov's rule states that in the addition of HX to an unsymmetrical alkene, the hydrogen adds to the carbon
ExplanationThis gives the more stable carbocation intermediate.
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Question 6 of 100
The functional group of alcohols is
ExplanationIt is the hydroxyl group.
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Question 7 of 100
Starch consists of amylose and amylopectin, while cellulose is composed of
ExplanationHumans cannot digest cellulose because they lack the enzyme cellulase.
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Question 8 of 100
The main component of natural gas is
ExplanationNatural gas is about 85–95% methane.
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Question 9 of 100
Polylactic acid (PLA) is considered environment-friendly because it is
ExplanationIt can be made from corn starch and breaks down under composting.
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Question 10 of 100
Terminal alkynes such as ethyne give a precipitate with ammoniacal silver nitrate because they have
ExplanationThe sp-hybridised C–H bond is acidic enough to be replaced by a metal, forming silver acetylide.
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Question 11 of 100
The hydration of ethene in the presence of an acid catalyst gives
ExplanationIt is an industrial method for making ethanol.
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Question 12 of 100
The functional group –COOH is present in
ExplanationIt is the carboxyl group.
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Question 13 of 100
Alkenes contain at least one
ExplanationThis makes alkenes unsaturated.
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Question 14 of 100
Polythene is formed by
ExplanationMonomers add without losing any small molecule.
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Question 15 of 100
The monomer of polystyrene is
ExplanationIt is C₆H₅–CH=CH₂.
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Question 16 of 100
Unlike soaps, detergents
ExplanationDetergents do not form insoluble scum with Ca²⁺ and Mg²⁺ ions.
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Question 17 of 100
Bakelite is a
ExplanationOnce set, it cannot be softened by heating again.
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Question 18 of 100
Alkanes mainly undergo ______ reactions, whereas alkenes mainly undergo ______ reactions.
ExplanationAlkenes have a reactive π bond that opens to add atoms.
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Question 19 of 100
In benzene, all carbon–carbon bonds are of equal length because of
ExplanationThe π electrons are spread over the six-carbon ring.
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Question 20 of 100
Vegetable oil is converted into vanaspati ghee by
ExplanationHydrogen is added to C=C bonds, making the fat solid.
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Question 21 of 100
Aspirin (acetylsalicylic acid) contains the functional groups
ExplanationIt is the acetate ester of salicylic acid.
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Question 22 of 100
The reaction between a carboxylic acid and an alcohol in the presence of an acid catalyst gives
ExplanationThis reaction is called esterification and esters have fruity smells.
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Question 23 of 100
Polystyrene is commonly used for
ExplanationExpanded polystyrene is lightweight and a good heat insulator.
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Question 24 of 100
Ethanol reacts with sodium metal to give
Explanation2C₂H₅OH + 2Na → 2C₂H₅ONa + H₂.
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Question 25 of 100
Compared with saturated fats, unsaturated fats
ExplanationDouble bonds create kinks that prevent close packing.
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Question 26 of 100
Breaking large hydrocarbon molecules into smaller, more useful ones is called
ExplanationIt is used to produce petrol and alkenes from heavy fractions.
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Question 27 of 100
The bond linking two amino acids in a protein is the
ExplanationIt is an amide linkage (–CO–NH–).
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Question 28 of 100
Cotton fibre is mostly
ExplanationCellulose is a natural polymer of glucose.
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Question 29 of 100
Denaturation of a protein involves
ExplanationHeat, acid or heavy metals disrupt hydrogen bonds and other forces.
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Question 30 of 100
In one molecule of ethene, the number of sigma (σ) and pi (π) bonds is
ExplanationFour C–H σ bonds, one C–C σ bond and one C–C π bond.
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Question 31 of 100
Hydrolysis of an ester with sodium hydroxide is called
ExplanationIt gives the sodium salt of the acid and an alcohol (soap and glycerol for fats).
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Question 32 of 100
Kevlar, used in bulletproof vests, is an
ExplanationStrong hydrogen bonding between chains makes it extremely strong.
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Question 33 of 100
Table sugar (sucrose) is a
ExplanationSucrose is a disaccharide of glucose and fructose.
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Question 34 of 100
The monomers of nylon-6,6 are
ExplanationThey form an amide linkage with loss of water.
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Question 35 of 100
Organic chemistry is the study of compounds of
ExplanationOrganic compounds contain carbon, usually bonded with hydrogen, oxygen, nitrogen, halogens and sulphur.
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Question 36 of 100
The Wurtz reaction involves the treatment of an alkyl halide with
Explanation2CH₃Cl + 2Na → C₂H₆ + 2NaCl.
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Question 37 of 100
The monomer of PVC is
ExplanationCH₂=CHCl polymerises to PVC.
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Question 38 of 100
The sour taste of lemons is due to
ExplanationCitric acid is an organic acid in citrus fruits.
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Question 39 of 100
The general formula of alkanes is
ExplanationAlkenes are CₙH₂ₙ and alkynes are CₙH₂ₙ₋₂.
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Question 40 of 100
Nylon-6,6 and polyesters are formed by
ExplanationA small molecule such as water is eliminated at each step.
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Question 41 of 100
Proteins are polymers of
ExplanationAmino acids join through peptide bonds.
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Question 42 of 100
Soap is prepared by the reaction of fats or oils with
ExplanationThis process is called saponification.
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Question 43 of 100
A series of compounds in which successive members differ by a –CH₂– group is a
ExplanationMembers show similar chemical properties and gradual change in physical properties.
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Question 44 of 100
Enzymes are
ExplanationThey speed up biochemical reactions.
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Question 45 of 100
Soap forms scum in hard water because of
ExplanationInsoluble calcium and magnesium salts of fatty acids form.
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Question 46 of 100
Ethyne (acetylene) gas is used for
ExplanationIts oxy-acetylene flame reaches about 3,000 °C.
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Question 47 of 100
The functional group –CHO is present in
ExplanationFormaldehyde (methanal) and acetaldehyde (ethanal) are examples.
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Question 48 of 100
Vulcanisation of rubber is the heating of rubber with
ExplanationIt makes rubber harder, stronger and more elastic.
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Question 49 of 100
The octane number is a measure of
ExplanationA higher octane number means less engine knocking.
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Question 50 of 100
PET, used for drink bottles, is a
ExplanationIt is polyethylene terephthalate.
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Question 51 of 100
Ziegler–Natta catalysts are used in the preparation of
ExplanationThey produce stereoregular linear polymers at low pressure.
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Question 52 of 100
The IUPAC name of CH₃CH₂OH is
ExplanationTwo carbons with an –OH group gives ethanol.
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Question 53 of 100
The silver mirror test (Tollens' test) is used to detect
ExplanationAldehydes reduce the silver(I) complex to metallic silver.
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Question 54 of 100
Petrol and diesel are obtained from crude oil by
ExplanationFractions are separated according to boiling points.
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Question 55 of 100
Concentrated H₂SO₄ is used in esterification mainly as a
ExplanationIt protonates the acid and removes water, shifting the equilibrium.
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Question 56 of 100
Dehydration of ethanol with concentrated H₂SO₄ at about 170 °C produces
ExplanationAt 140 °C diethyl ether is the main product.
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Question 57 of 100
Which of the following is a natural polymer?
ExplanationProteins, starch, cellulose, rubber and DNA are natural polymers.
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Question 58 of 100
The number of structural isomers of pentane (C₅H₁₂) is
Explanationn-pentane, isopentane (2-methylbutane) and neopentane (2,2-dimethylpropane).
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Question 59 of 100
Compounds having the same molecular formula but different structures are called
ExplanationFor example, butane and isobutane are both C₄H₁₀.
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Question 60 of 100
Acetone (propanone) belongs to the family of
ExplanationIt contains a C=O group between two carbon atoms.
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Question 61 of 100
The molecular formula of glucose is
ExplanationGlucose is a monosaccharide and the main energy source of cells.
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Question 62 of 100
Teflon is widely used for
ExplanationIt is chemically inert and resists heat.
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Question 63 of 100
The molecular formula of benzene is
ExplanationBenzene is the simplest aromatic hydrocarbon.
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Question 64 of 100
Ethanol, found in alcoholic drinks, belongs to the family of
ExplanationIts functional group is –OH.
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Question 65 of 100
The balanced equation for the complete combustion of methane is
ExplanationThe reaction is exothermic.
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Question 66 of 100
Biogas obtained from animal dung mainly contains
ExplanationIt forms by anaerobic decomposition of organic matter.
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Question 67 of 100
Oxidation of a secondary alcohol gives a
ExplanationA primary alcohol gives an aldehyde, then a carboxylic acid.
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Question 68 of 100
Polythene (polyethylene) is made from the monomer
ExplanationMany ethene units join to form polyethene.
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Question 69 of 100
Ethanol (C₂H₅OH) and dimethyl ether (CH₃OCH₃) are examples of
ExplanationThey have the same formula C₂H₆O but different functional groups.
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Question 70 of 100
Nylon is a
ExplanationIt is a polyamide used in fibres, ropes and fabrics.
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Question 71 of 100
Alkanes are
ExplanationThey contain only single C–C bonds.
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Question 72 of 100
The sting of ants and bees contains
ExplanationIt causes pain and irritation of the skin.
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Question 73 of 100
According to Hückel's rule, a planar cyclic compound is aromatic if it has ______ π electrons.
ExplanationBenzene has 6 π electrons (n = 1).
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Question 74 of 100
LDPE differs from HDPE in that LDPE
ExplanationHDPE is linear, packs closely, and is made with Ziegler–Natta catalysts.
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Question 75 of 100
The IUPAC name of CH₃–CH(CH₃)–CH₃ is
ExplanationThe longest chain has three carbons with a methyl at C-2.
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Question 76 of 100
The number of structural isomers of butane (C₄H₁₀) is
Explanationn-butane and 2-methylpropane (isobutane).
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Question 77 of 100
Natural rubber is a polymer of
ExplanationIt is cis-1,4-polyisoprene.
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Question 78 of 100
Vinegar contains
ExplanationVinegar is about 4–8% acetic acid in water.
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Question 79 of 100
The fermentation of glucose by yeast gives
ExplanationThe enzyme zymase catalyses the reaction.
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Question 80 of 100
Starch is a polymer of
ExplanationPlants store energy as starch.
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Question 81 of 100
The H–C–H bond angle in methane is
ExplanationMethane is tetrahedral (sp³); ethene is 120° (trigonal planar) and ethyne is 180° (linear).
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Question 82 of 100
Methanol, also called wood spirit, is
ExplanationIt can cause blindness and death if consumed.
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Question 83 of 100
The ability of carbon atoms to join with one another forming long chains is called
ExplanationThis is why carbon forms so many compounds.
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Question 84 of 100
Rubber obtained from rubber trees is a
ExplanationNatural rubber comes from latex.
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Question 85 of 100
The valency of carbon is
ExplanationCarbon forms four covalent bonds.
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Question 86 of 100
The molecular formula of propane is
ExplanationFor n = 3: CₙH₂ₙ₊₂ = C₃H₈.
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Question 87 of 100
A carbon atom attached to four different groups is called
ExplanationIt gives rise to optical isomerism.
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Question 88 of 100
Cooking oils and fats belong to a class of biomolecules called
ExplanationThey are esters of glycerol and fatty acids.
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Question 89 of 100
Cis–trans isomerism is shown by
ExplanationRestricted rotation around C=C with different groups on each carbon gives geometrical isomers.
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Question 90 of 100
The hybridisation of carbon atoms in ethene and ethyne respectively is
ExplanationMethane is sp³, ethene sp² and ethyne sp.
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Question 91 of 100
Silk and wool are made mainly of
ExplanationThey are natural protein fibres.
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Question 92 of 100
The simplest hydrocarbon is
ExplanationMethane (CH₄) has one carbon atom.
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Question 93 of 100
Benzene mainly undergoes
ExplanationSubstitution keeps the stable aromatic ring intact.
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Question 94 of 100
Bromine water is decolourised by
ExplanationIt is a test for unsaturation (C=C or C≡C).
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Question 95 of 100
Oxidation of ethanol with an oxidising agent gives
ExplanationEthanol → ethanal → ethanoic acid.
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Question 96 of 100
LPG mainly consists of
ExplanationIt is stored as a liquid under pressure.
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Question 97 of 100
Thermosetting plastics are hard and heat-resistant because of
ExplanationCross-links form a rigid 3D network.
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Question 98 of 100
PVC stands for
ExplanationIt is used in pipes, cables and flooring.
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Question 99 of 100
Complete combustion of a hydrocarbon in plenty of oxygen produces
ExplanationCombustion releases heat energy.
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Question 100 of 100
Soap molecules are
ExplanationSoap has a hydrophilic head and a hydrophobic tail.
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