Question

Which of the following is used as an anti-knocking material?
A. T.E.L
B. ${C_2}{H_5}OH$
C. Glyoxal
D. Freon

Answer 1

We know that anti-knocking agents are the additive compounds used to prevent knocking in fuel used in engines. Knocking is the process in which the fuel used in an engine does not ignite (starts burning in order to provide energy) from the ignite fuse but from some other source/pocket in the engine. Anti-knocking agents reduce this property in engines.

Complete step by step answer:
T.E.L or TetraEthyl Lead has been widely used for an anti-knocking agent in fuels. This compound increases the octane content in petrol and hence is useful in reducing engine knocking. But these days it is replaced with compounds like ferrocene, MMT, etc. due to lead in it.
${C_2}{H_5}OH$ or Ethanol is used as an additive or anti knocking agent with gasoline. Ethanol use in fuel is permitted up to 10% only. But due to its high manufacturing cost and transportation, use of ethanol is restricted as an anti-knocking agent.
Glyoxal is an organic compound used in many chemical processes like wood hardening, leather preservation, cell preservation for microscopy etc. This chemical is used as a solubilizer which increases solubility of compounds but not used as an anti-knocking additive in petrol.
Freon is a type of chlorofluorocarbon which is a type of gas. This compound was used for refrigeration and cannot be dissolved as an additive for anti-knocking property in oils. Hence, it is not used.
Hence, we have two correct answers, option A and option B.

Hence, the correct answer is A,B.

Note: To bring into our knowledge, anti-knocking agents improve the octane rating of gasoline. High octane rating means the oil in the engine can be more compressed before combustion which prevents the burning of oil before reaching the ignition point. Hence oils with high octane number are good oils. Addition of Tetraethyl lead in oil is known as doping. Addition of a small amount of anti-knocking increases the octane value to a large extent. Also, T.E.L is colourless but in order to prevent poisoning with it, it is coloured before adding to petrol which gives oil its colour.