Reaction Mechanism Questions

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).Assertion (A) : 1-iodobutane undergoes ${\text{S}}_{\text{N}}2$ reaction faster than 1-chlorobutane.Reason (R) : Iodine is a better leaving group because of its large size.In the light of the above statements, choose the correct answer from the options given below :

Which one is a nucleophilic substitution reaction among the following?

The reaction of hydrogen and iodine monochloride is given as:${\text{H}}_2(g)+2\text{ICl}(g)\to 2\text{HCl}(g)+{\text{I}}_2(g)$ This reaction is of first order with respect to ${\text{H}}_2(g)$ and $\text{ICl}(g)$. The following mechanisms were proposed:Mechanism A: ${\text{H}}_2(g)+2\text{ICl}(g)\to 2\text{HCl}(g)+{\text{I}}_2(g)$ Mechanism B:${\text{H}}_2(g)+\text{ICl}(g)\to \text{HCl}(g)+\text{HI}(g)$ (slow)$\text{HI}(g)+\text{ICl}(g)\to \text{HCl}(g)+{\text{I}}_2(g)$ (fast)Which mechanism is consistent with the rate law?

The major product of the reaction between an alkene and $\text{HBr}$ in the presence of peroxides is governed by:

In the following reaction:

The major product $A$ is:

For the following reactions:

Which of the following statements is correct?