13.18. Arrange benzene, n-hexane and ethyne in decreasing order of acidic behaviour. Also give reason for this behaviour.

HBr adds to alkene in accordance with Markovnikov's rule.

Delocalisation of  electrons in benzene  leads to saturation

To study Hydrocarbons for NEET, you can use the Hydrocarbons Class 11th NCERT solutions PDF.

Alkanes, Alkenes, Alkynes, and Aromatics hydrocarbons are the four main hydrocarbons.

Hydrocarbons are organic compounds made of only carbon and hydrogen.