Question

The reaction of propene with $HOCl$ proceeds via the addition of,
A)$C{l}^{+}\mathrm{\&}O{H}^{-}$ in a single step.
B)$C{l}^{+}$ in the first step.
C)$H^{+}$ in the first step.
D)$O{H}^{-}$ in the first step.

Answer 1

Hint:We know that electrophilic addition is a reaction between an electrophile and nucleophile, adding to double or triple bonds. A molecule that tends to react with other molecules containing a donatable pair of electrons is called an electrophile.

Complete step by step answer:

The Bronsted Lowry theory is based on an acid and base reaction.
We know that an acid is a species which has the capacity of donating a proton that is hydrogen ion is called Bronsted-Lowry acid and a base is a species which has the capacity of accepting proton and a base it needs to have a lone pair of electrons on the base which bonds to the hydrogen ion.
Now, we see Conjugate acid.
According to Bronsted-Lowry theory, the conjugate acid is the chemical species which is formed after the base accepts the hydrogen atom is called conjugate acid.
$Acid+Base\rightleftharpoons ConjugateBase+ConjugateAcid$
In the case of hypochlorous and hypobromous acids $$\left(HOX\right)$$ these weak Bronsted acids do not react as proton donors; and since oxygen is more electronegative than chlorine or bromine, the electrophile will be a halide cation.
Alkenes undergo Electrophilic addition reactions on self-ionization produces $C{l}^{+}$ ion. This chloride ion attacks the propene first.
$HOCl+HOCl\stackrel{}{\to }{H}_{2}O+OC{l}^{-}+C{l}^{+}$
Therefore, option B is correct.

Note:
We must remember when ethylene on addition with hypochlorous acid forms a product where double bond breaks and electrophile and nucleophile addition take place.
The product is,
$$C{H}_2=C{H}_2\stackrel{HOCl}{\to }HO-C{H}_2-C{H}_2-Cl$$