To which of the following four types does this reaction belong: $B^{-} + R - A \to B - R + A^{-}$?

Which one of the following statements is $True$?

The given reaction is a pinacol-pinacolone rearrangement. Which of the following is not correct about the product formed?

What is the fission of covalent bonds?

The order of decreasing reactivity in electrophilic addition of the following compounds is
$(I) \, Ph-CH=CH-COOH$
$(II) \, p-NO_2-C_6H_4-CH=CH-COOH$
$(III) \, p-MeO-C_6H_4-CH=CH-COOH$
$(IV) \, p-Cl-C_6H_4-CH=CH-COOH$

Fill in the blanks:
$(1)$ ......... is the name of $C_6H_5Br_2$.
$(2)$ .......... and ......... are the suffixes for aldehyde and hydroxyl functional groups,respectively.
$(3)$ $A$ is formed by homolytic fission,while $B$ is formed by heterolytic fission of the $C-Cl$ bond in $CH_3-Cl$.
$(4)$ The fission of a covalent bond is of ......... and ......... type.