The major product of the reaction of $2$ -butene with alkaline ${\mathrm{KMnO}}_4$ solution is

What are $\mathrm{A}$ and $\mathrm{B}$ in the following?

The reactivity order towards hydrogenation of the following compounds is:

(I) ${\mathrm{CH}}_3-\mathrm{C}\equiv \mathrm{C}-{\mathrm{CH}}_3$

(II) 

(III) 

(IV) 

Name the reaction?

${\mathrm{C}}_3{\mathrm{H}}_6\to {\mathrm{C}}_3{\mathrm{H}}_8$

What are $\mathrm{A}$ and $\mathrm{B}$ in the following?

The major product of the following reaction

 is