Butane (C4H10) is produced in industry by the THERMAL cracking of long-chain
hydrocarbon molecules, as shown in the equation below. X represents an organic
compound that is produced.
4.1 Write down:
4.1.1 ONE condition required for THERMAL cracking to take place (1)
4.1.2 The molecular formula of compound X (1)
4.1.3 The homologous series to which compound X belongs (1)
4.2 A mixture of the two gases, compound X and butane, is bubbled through bromine water, Br2(aq), in a conical flask, as illustrated below. THE REACTION IS CARRIED OUT IN A DARKENED ROOM.
The colour of the bromine water changes from reddish brown to colourless when the mixture of the two gases is bubbled through it.
Which ONE of the gases (X or BUTANE) decolorises the bromine water?
Explain the answer. (4)
4.3 Study the flow diagram below, which represents various organic reactions,
and answer the questions that follow.
Write down the:
4.3.1 IUPAC name of compound P (2)
4.3.2 Type of reaction labelled I (1)
4.3.3 Structural formula of compound Q (2)
4.3.4 The type of addition reaction represented by reaction III (1)
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