Haloalkanes and Haloarenes Test - 6

This is electrophilic addition reaction following Markovnikoffs rule.and negative part that is I will go to the carbon having lesser number of hydrogen.

Halide exchange reaction is Finkelstein reaction in which alkyl chloride is converted to alkyl iodide.
The classic Finkelstein reaction entails the conversion of an alkyl chloride or an alkyl bromide to an alkyl iodide by treatment with a solution of sodium iodide in dry acetone. Sodium iodide is soluble in acetone and sodium chloride and sodium bromide are not. The reaction is driven toward products according to Le chatelier's principle due to the precipitation of the salt insoluble in acetone. For example, in this case chloropropane can be converted to iodopropane:
CH₃CH₂CH₂Cl_(acetone) + NaI_(acetone) → CH₃CH₂CH₂I_(acetone) + NaCl _(s)

Alkyl fluorides is only formed by Swartz reaction.in swartz reaction alkyl chlorides or bromide reacts with metallic flouride AgF Hg₂F₂ to form alkyl flourides.

For SN₂ reaction leaving group should be good and alkyl halide should be primary.so CH₃Br and CH₃Cl are 1⁰organic compounds hence rate of  sn₂ reaction will be more.

The nucleophilic substitution in S_N1 occurs in two steps. In step I, the polarised C—Br bond undergoes slow cleavage to produce a carbocation and a bromide ion. This is the slow rate determining step. Thus, the stability of the carbocation formed determines the rate of reaction. The carbocation thus formed is then attacked by nucleophile in step II to complete the substitution reaction.
In C₆H₅C(CH₃)(C₆H₅)Br carbocation will be tertiary and will be resonance stablised. So the rate of S_N1 reaction is greatest in this case. In case of C₆H₅CH(C₆H₅)Br, the carbocation formed will be secondary and hence less stable than the previous one, so the reaction will be slower in this case. In C₆H₅CH(CH₃)Br, the carbocation formed will be less stable than that formed in case of C₆H₅CH(C₆H₅)Br because in the latter the carbocation is stabilised by two phenyl groups due to resonance. In C₆H₅CH₂Br, the carbocation formed will be primary and hence least stable causing the rate of reaction to be least in this case.

CHCl₃ on reaction with oxygen forms phosgene. Chloroform decomposes when it exposed to sunlight.it decomposes to a harmful gas phosgene(COCl₂) Chloroform decomposes when it exposed to sunlight.it decomposes to a harmful gas phosgene(COCl₂)

Since halogen atoms are more electronegative than carbon, the carbon-halogen bond of alkyl halide is polarised; the carbon atom bears a partial positive charge whereas the halogen atom bears a partial negative charge. This is responsible for nucleophilic substitution reactions, elimination reactions and reaction of alkyl halides with a metal to form organometallic compounds.