O.P Tandon Test: Hydrocarbons - JEE MCQ

2 Na atoms are used.

Ortho , meta and para.

 is incomplete combustion.

It is a terminal alkyne, having acidic hydrogen.

Elimination reaction takes place.

Infinite conformational isomers of ethane is possible since continuous rotations around C-C bond is there.

Continuous delocalization of pi electron or resonace in benzene

Methyl group is electron donating group, hence increase electron density in benzene ring.

Methane is produced by reaction with grignard reagent.

Ethyne gas(Acetylene) is prepared in the laboratory by the action of water on calcium carbide.

CaC₂ +  2H₂O  ----------> C₂H₂ + Ca(OH)₂   

As molecular mass increase boiling point increases.

Huckel rule.

Neopentane with Cl₂​ and monohalogenation gives single product.

 In this reaction we are not using AlCl_3​ we are using direct Cl_2​ gas in presence of strong radiation-Ultraviolet which is then able to break open the double bonds of the benzene ring and facilitate the approach of the reactive intermediate of chlorine, most probably a free radical of Cl^. since it is believed if the reaction proceeds by free radical mechanism this way all the carbons of benzene will have equal share of electron (moreover in the space freons disturbs ozone layer because they are able to form free radicals with UV rays). So it is believed it proceeds via free radical mechanism and hence form gammaexane(gamma isomer) with other minor isomers of C₆​Cl₆​H_6​.

Ethyne (C₂H₂) and CO_2.accompanied with the formation of KOH and H₂.

Hence B is correct.

Alkane halogenation is an example of a substitution reaction, a type of reaction that often occurs in organic chemistry. A substitution reaction is a chemical reaction in which part of a small reacting molecule replaces an atom or a group of atoms on a hydrocarbon or hydrocarbon derivative.

All of the mentioned methods can be used but the commercially used method is from the isolation from coal tar.

Wurtz reaction is used to make symmetrical hydrocarbons thus it cannot be used to make ethyl benzene.

Cycloalkanes have general formula of C_nH_2n

Dehydrohalogenation takes place. Preparation of alkyne by heating ethylene chloride with alc. KOH followed by sodamide in ammonia solution.

sigma bond is formed by head-on overlap, pi bond is formed by lateral overlap. Alkenes contain 1 pi bond and 1 sigma bond.

anhydrous alluminium chloride produces electrophile to attack benzene.

Dehydration of alcohols is done in presence of alumina at 3500−4000 and by this process alkene is obtained.