Organic chemistry

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Question 23
Medium

A heavy fraction of crude oil containing tetracosane, C24H50\text{C}_{24}\text{H}_{50}C24​H50​, is thermally cracked in a refinery to produce dodecane, C12H26\text{C}_{12}\text{H}_{26}C12​H26​, and another short-chain hydrocarbon as shown below:

C24H50→C12H26+4 …………\text{C}_{24}\text{H}_{50} \rightarrow \text{C}_{12}\text{H}_{26} + 4 \, \dots\dots\dots\dotsC24​H50​→C12​H26​+4…………

a.

Complete the balanced symbol equation for this cracking reaction by finding the missing chemical formula.

[1]
b.

A laboratory technician has two unlabelled bottles containing colourless liquids: Compound P (C5H12\text{C}_5\text{H}_{12}C5​H12​) and Compound Q (C5H10\text{C}_5\text{H}_{10}C5​H10​). To identify them, the technician adds a few drops of orange-brown bromine water to a sample of each compound.

Explain, in terms of their bonding, why Compound Q decolourises the bromine water whereas Compound P does not.

[2]
c.

Write the balanced symbol equation for the addition reaction of Compound Q with bromine, Br2\text{Br}_2Br2​.

[1]

Organic chemistry Questions

  1. GCSE
  2. /Chemistry
  3. /Organic chemistry