Alkanes

  • M/J 2019/P12/Q35

Which reaction is an addition reaction?

A ​​ ​​​​ making ethane and ethene from butane

B ​​ ​​​​ making ethene and hydrogen from butane

C ​​ ​​​​ the manufacture of margarine from a vegetable oil

D​​ the reaction between ethene and oxygen, giving carbon dioxide  ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​​​ and water

Answer: ​​ C

Explaination

Addition reaction comes under the chemical reaction of alkenes in which atoms are added across the double bond results in a single saturated product.

Option A and B are the examples of cracking as in this process large alkane molecules are cracked to form smaller hydrocarbon molecules.

Option C is correct as alkenes are unsaturated HC ​​ contains C=C. The​​ manufacturing of margarine from a vegetable comes under addition reaction of alkene (hydrogenation), in which atoms are added across the double bond of alkene results in a single saturated product.

Option D is a combustion reaction in which alkene burn with oxygen to give CO2​​ and H2O.