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JAMB Chemistry 1986 Question 42

Question 42

Petroleum and Coal

Which of the following is used as an 'anti-knock' in automobile engines?

  1. A.Tetramethyl silane
  2. B.Lead tetra-ethyl
  3. C.Glycerol
  4. D.n-heptane
Show the answer and explanation

Answer: B (Lead tetra-ethyl)

Explanation

Tetraethyl lead was added to petrol to stop knocking (early ignition). n-Heptane knocks badly and is the zero of the octane scale.