Which step is the chain termination step in the following mechanism?

$\left(\mathrm{i}\right)<mspace\; width="1em"></mspace>{\mathrm{Cl}}_2\stackrel{h\nu }{\to }{\mathrm{Cl}}^{\bullet }+{\mathrm{Cl}}^{\bullet }$
$\left(\mathrm{ii}\right)<mspace\; width="1em"></mspace>{\mathrm{Cl}}^{\bullet }+<mspace\; width="1em"></mspace>{\mathrm{CH}}_4\to \stackrel{\bullet }{{\mathrm{CH}}_3}+<mspace\; width="1em"></mspace>\mathrm{HCl}$
$\left(\mathrm{iii}\right)\stackrel{\bullet }{\mathrm{C}}{\mathrm{H}}_3+{\mathrm{Cl}}_2\to {\mathrm{CH}}_3\mathrm{Cl}+{\mathrm{Cl}}^{\bullet }$
$\left(\mathrm{iv}\right){\mathrm{Cl}}^{\bullet }+\stackrel{\bullet }{\mathrm{C}}{\mathrm{H}}_3\to {\mathrm{CH}}_3\mathrm{Cl}$

1. (i)

2. (ii)

3. (iii)

4. (iv)

The elimination reaction among the following is:

1. CH₃CH₃+Cl₂$\to$CH₃CH₂Cl+ HCl

2. CH₃Cl+ KOH(aq.) $\to$CH₃OH +KCl

3. CH₂=CH₂ +Br₂ $\to$CH₂BrCH₂Br

4. C₂H₅Br+ KOH(alc.) $\to$C₂H₄ + KBr+H₂O

Which of the following is an example of the elimination reaction?

1. Chlorination of methane

2. Dehydration of ethanol

3. Nitration of benzene

4. Hydroxylation of ethylene

Which of the following is the most correct electron displacement for a nucleophilic reaction to take place? 

1.
2.
3.
4.

Consider the following statements:

a. Benzene gives substitution reaction more readily than addition reaction.

b. In benzyne mechanism reaction intermediate is carbanion also.

c. Tertiary alcohol always gives S_N¹ reaction.

d. Reactivity of alcohol is very poor for SN reaction because alcohol is strongly acidic in character.

Of these statements :

1. only a is correct.

2. a and c are correct

3. a, b, and d are correct

4. a, b and c are correct