Convert the following :
(a)
(b)`underset((I))(PhH("Benzene"))underset((II))(PhCOOH)("Benzoic acid")`
( c)
(d)
( e)
(f)
(g)
(h)
(i) `underset((I))(MeCOOH)("Acetic acid") rarr underset((II))underset(("Malonic acid"))((CH_(2)(COOH)_(2)))`

Explanation

(a) Here a `2 C` atom step up method is needed. Convert `(I)` to dibromo compound and then use cyanide method which on acidic hydrolysis gives `4C-acid`.

(b) First method :
Convert `(I)` to toluence by `F.C` alkylation, which on oxidation gives `(II)`.
`underset ((I)) (PhH) overset(CH_3Cl + AlCl_3) underset(F.C. alkylation)rarr PhMe overset([O]) underset (KMnO_4//H^(oplus))rarr underset((II)) (PhCOOH)`
Second method :
Convert `(I)` to `PhBr` and use Grignard method to obtain `(II)`.
`underset((I))(PhH)overset(Br_(2))underset(FeBr_(3))rarrPhBr underset(underset(3.H_(3)O^(o+))(2.CO_(2)))overset(1.Mg//ether)rarr underset((I))(PhCOOH)`
( c) Introduce two `(Br)` groups in benzene, and then use Grignard method, followed by oxidation of `(Me)` to `(-COOH)`.

(d) First introduce `(-NO_2)`group at `p-position` by nitration of `(I)`, followed by chlorination and oxidation,

( e) Allylic or benzylic chlorination by `Cl_2//hv` or `Cl_2 SO_2` (sulfuryl chloride) or `Me_3 COCl` (t-butyl hypochlorite), followed by dicarbonation by Grinard method.

Note : `ArCl` (Aryl chloride) in ether `(Et_2O)` is inert to Grignard formation but reacts in `THF` (tetrahydrofuran or oxacyclopentane), However, `ArBr` (aryl bromide) in ether reacts with `Mg` to form `G.R`.
(f) Introduce `(Br)` or `(Cl)` group at `p-position` of `(I)` followed by carbonation by using `G.R`.

(g) First introduce `(Cl)` group at p-position and then `(Br)` group at `o-position` w.r.t. `(Me)` group, followed by carbonation by `G.R` Carbonation will take place with `(Br)` group and not with `(Cl)` group, since `Br` is more reactive than `Cl`.

(h) This problem is similar to the probelm in `(g)`. First introduce `(Br)` group at `p-position` and then `(Cl)` group at `o-position` w.r.t. `(Me)` group, followed by carbonation will `Br`.
.