Moderate

Which of the following statements is/are correct?

Correct answer: D. A and C only

  • A. Alkanes and alkenes can be distinguished by Br2/CCl4, Baeyer's test
  • B. Alkanes and alkynes can be distinguished by Br2/CCl4, Baeyer's test
  • C. Alkyne-1 and alkyne-2 can be distinguished by Cu2Cl2/NH4OH, AgNO3/NH4OH
  • D. A and C only

Explanation

alkanes and alkenes can be distinguished using the Baeyer's test, which involves the reaction of the compounds with bromine (Br2) in carbon tetrachloride (CCl4) solvent.Baeyer's test is a chemical test used to differentiate between alkanes and alkenes based on their reactivity towards bromine. It exploits the difference in reactivity of alkanes and alkenes towards bromine, which is an electrophilic reagent.Reaction with Alkanes: Alkanes are relatively unreactive compounds. When an alkane is mixed with Br2 in CCl4, there is little to no reaction observed. The bromine remains orange or red-brown, indicating no significant reaction with the alkane.Reaction with Alkenes: Alkenes, on the other hand, are more reactive due to the presence of the π (pi) bond. When an alkene is mixed with Br2 in CCl4, a rapid and characteristic reaction occurs. The orange or red-brown color of bromine quickly disappears, and the solution becomes colorless. This is because the alkene undergoes electrophilic addition with bromine, breaking the π bond and forming a dibromoalkane. The decolorization of bromine is a positive test for the presence of an alkene.The reaction of bromine with alkenes in Baeyer's test is an example of electrophilic addition, where the π electrons of the double bond act as nucleophiles and attack the electrophilic bromine.In summary, Baeyer's test using Br2/CCl4 is a simple and effective method to distinguish between alkanes (no reaction) and alkenes (rapid decolorization) based on their different reactivities towards bromine

Last updated

About Chemistry of Hydrocarbons

Hydrocarbons are studied through the structures and reactions of alkanes, alkenes, alkynes and aromatic compounds. Coverage includes free radical substitution in alkanes, electrophilic addition to carbon-carbon multiple bonds, benzene substitution, aromatic stability and the difference between addition reactions of alkenes and substitution reactions of benzene.

Practise Chemistry of Hydrocarbons

1,091 free Chemistry of Hydrocarbons MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.

Exams that ask Chemistry questions like this

Chemistry is on 12 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.

Related questions