FREE Gaokao Chemistry: Organic Chemistry Fundamentals Questions and Answers

Question 1

Which of the following pairs of substances are isomers of each other?

Accepted Answer

Ethanol (C2H5OH) and Dimethyl ether (CH3OCH3)

Answer

Isomers are compounds that have the same molecular formula but different structural formulas. Both ethanol (CH3CH2OH) and dimethyl ether (CH3OCH3) share the molecular formula C2H6O, but their functional groups and structures are different, making them isomers.

Question 2

Which of the following organic compounds can decolorize both acidic potassium permanganate (KMnO4) solution and bromine water?

Accepted Answer

Ethene

Answer

Ethene contains a carbon-carbon double bond (C=C). This unsaturated bond can undergo an addition reaction with bromine water and an oxidation reaction with acidic KMnO4, causing both reagents to lose their color. Saturated compounds like ethane do not react, while ethanol only reacts with KMnO4.

Question 3

What is the correct IUPAC name for the compound with the structure CH3CH(CH3)CH2COOH?

Accepted Answer

3-Methylbutanoic acid

Answer

For naming carboxylic acids, the longest carbon chain including the carboxyl group is identified, and numbering starts from the carboxyl carbon as C1. The chain has four carbons (butanoic acid), and a methyl group is attached to the third carbon (C3).

Question 4

The reaction of benzene with concentrated nitric acid and concentrated sulfuric acid at 50-60°C to produce nitrobenzene is an example of what type of reaction?

Accepted Answer

Substitution reaction

Answer

This reaction involves the replacement of a hydrogen atom on the benzene ring with a nitro group (-NO2). A reaction where an atom or group of atoms is replaced by another atom or group is known as a substitution reaction. Specifically, this is an electrophilic aromatic substitution.

Question 5

Which of the following statements correctly describes a property of ethanoic acid (acetic acid)?

Accepted Answer

It can react with sodium carbonate to produce CO2 gas.

Answer

Ethanoic acid is a weak acid, meaning it only partially ionizes in aqueous solution to produce H+ ions and ethanoate ions. Its acidity is greater than that of carbonic acid, allowing it to react with carbonates like sodium carbonate (Na2CO3) to produce carbon dioxide gas.

Gaokao Exam Practice Test

Gaokao Exam Practice Test

FREE Gaokao Chemistry: Organic Chemistry Fundamentals Questions and Answers