Organic Chemistry questions

By Interwoven Maths

Organic Chemistry question collection

Review Organic Chemistry questions for Chemistry, with correct answers shown and coverage across crude oil and fractional distillation; alkanes and alkenes; combustion and cracking.

Back to Organic Chemistry practice Back to Chemistry

Question 1

Crude oil is best described as?
  1. A finite mixture of hydrocarbons
  2. A pure alkane
  3. A renewable biofuel
  4. A compound made only of carbon

Question 2

Which elements does a hydrocarbon contain?
  1. Carbon and hydrogen only
  2. Carbon, hydrogen and oxygen
  3. Carbon and oxygen only
  4. Hydrogen and oxygen only

Question 3

What is the general formula for alkanes?
  1. CnH2n+2
  2. CnH2n
  3. CnHn
  4. CnH2n-2

Question 4

Which formula is hexane?
  1. C6H14
  2. C6H12
  3. C6H6
  4. C6H16

Question 5

Which carbon-bond pattern is saturated?
  1. Single bonds only
  2. At least one double bond
  3. At least one triple bond
  4. Alternating single and double bonds

Question 6

What are the products of complete alkane combustion?
  1. Carbon dioxide and water
  2. Carbon monoxide and water
  3. Carbon and water
  4. Carbon dioxide and hydrogen

Question 7

When is incomplete combustion more likely?
  1. A limited supply of oxygen
  2. An excess of oxygen
  3. A catalyst
  4. Low pressure nitrogen

Question 8

Why is carbon monoxide dangerous?
  1. Competes with oxygen for haemoglobin
  2. Inflames lungs as an acidic gas
  3. Damages DNA with ionising radiation
  4. Displaces oxygen while chemically inert

Question 9

As alkane chains lengthen, their boiling points...
  1. Increase
  2. Decrease
  3. Stay constant
  4. Rise then fall

Question 10

Why do longer-chain hydrocarbons have higher boiling points?
  1. They have stronger intermolecular forces between molecules
  2. They have ionic bonds between molecules
  3. Their covalent bonds are easier to break
  4. They contain more oxygen atoms

Question 11

Fractional distillation separates crude oil fractions mainly by differences in what property?
  1. Boiling point
  2. Colour
  3. pH
  4. Density

Question 12

Where are low-boiling fractions collected in a fractionating column?
  1. Near the top
  2. Near the bottom
  3. Around the middle
  4. At several levels

Question 13

Which purpose does cracking serve?
  1. Increasing short-chain fuel supply
  2. Removing sulfur compounds
  3. Separating boiling-point fractions
  4. Converting alkenes into polymers

Question 14

Which conditions are used for catalytic cracking?
  1. High temperature and catalyst
  2. Low temperature and catalyst
  3. High temperature and water
  4. Ultraviolet light and chlorine

Question 15

What is the general formula of alkenes?
  1. CnH2n
  2. CnH2n+2
  3. CnHn
  4. CnH2n-2

Question 16

What forms when ethene reacts with hydrogen?
  1. Ethane
  2. Ethanol
  3. Ethanoic acid
  4. Poly(ethene)

Question 17

What product forms when ethene is hydrated?
  1. Ethanol
  2. Ethanoic acid
  3. Methanol
  4. Propane

Question 18

Which process produces ethanol by fermentation?
  1. Yeast without oxygen
  2. Ethene with steam
  3. Alkanes over a catalyst
  4. Ethanol with acidified dichromate

Question 19

Carboxylic acids in water are generally?
  1. Weak acids
  2. Strong alkalis
  3. Neutral salts
  4. Insoluble bases

Question 20

Which equation represents complete combustion of ethene?
  1. \(\mathrm{C}_{2}\mathrm{H}_{4} + 3\mathrm{O}_{2} \to 2\mathrm{CO}_{2} + 2\mathrm{H}_{2}\mathrm{O}\)
  2. \(\mathrm{C}_{2}\mathrm{H}_{4} + \mathrm{O}_{2} \to 2\mathrm{CO} + 2\mathrm{H}_{2}\)
  3. \(\mathrm{C}_{2}\mathrm{H}_{4} + 2\mathrm{O}_{2} \to 2\mathrm{CO}_{2} + 2\mathrm{H}_{2}\)
  4. \(2\mathrm{C}_{2}\mathrm{H}_{4} + \mathrm{O}_{2} \to 4\mathrm{CO}_{2} + 2\mathrm{H}_{2}\mathrm{O}\)

Question 21

Ethanol reacts with ethanoic acid. Which products form?
  1. Ethyl ethanoate and water
  2. Ethene and water
  3. Ethanal and hydrogen
  4. Methanol and carbon dioxide

Question 22

Which description is cracking?
  1. Splitting long hydrocarbons into shorter ones
  2. Joining alkenes into polymers
  3. Separating fractions by boiling point
  4. Oxidising alcohols into acids

Question 23

Why are alkenes more reactive than alkanes?
  1. They contain a carbon-carbon double bond
  2. They contain fewer carbon atoms
  3. They contain ionic bonds
  4. They have only single carbon-carbon bonds

Question 24

Which gas forms when a carboxylic acid reacts with a carbonate?
  1. Carbon dioxide
  2. Hydrogen
  3. Oxygen
  4. Methane

Question 25

What colour change shows bromine water reacting with an alkene?
  1. Orange to colourless
  2. Colourless to orange
  3. Blue to red
  4. Green to purple

Question 26

Which functional group defines an alcohol?
  1. Hydroxyl
  2. Carboxyl
  3. Carbonyl
  4. Amino

Question 27

Which pair are common uses of ethanol?
  1. Fuel and solvent
  2. Fuel and oxidiser
  3. Fertiliser and solvent
  4. Catalyst and refrigerant

Question 28

Which functional group defines a carboxylic acid?
  1. Carboxyl
  2. Hydroxyl
  3. Carbonyl
  4. Ester

Question 29

Which molecules form addition polymers?
  1. Alkene monomers
  2. Alkane molecules
  3. Alcohol molecules
  4. Carboxylic acids

Question 30

Which property makes many polymers persist in landfill?
  1. Slow biodegradation
  2. High water solubility
  3. Low melting point
  4. Rapid oxidation

About this topic

Review Organic Chemistry questions for Chemistry, with correct answers shown and coverage across crude oil and fractional distillation; alkanes and alkenes; combustion and cracking.

This topic covers

Example question types