The product $(B)$ in the given reaction is:

In the presence of peroxide,hydrogen chloride and hydrogen iodide do not give anti-Markovnikov's addition to alkenes because

Glycol on treatment with $PI_3$ mainly gives -

Upon heating with acidic $KMnO_4$,an organic compound produces hexan$-1,6-$dioic acid as the major product. The starting compound is

Which of the following gases decolourises $KMnO_4$ solution but does not give a precipitate with ammoniacal cuprous chloride?

Assertion $(A)$: Reaction of $but-1-ene$ with $HBr$ gives $1-bromobutane$ as the major product.
Reason $(R)$: Addition of $HBr$ to unsymmetrical alkenes proceeds according to Markovnikov's rule.
The correct answer is