The hottest region of the Bunsen flame shown in the figure below is:

Octane number can be changed by

Rank the following in the increasing order of rate of reaction with $HBr$.

The unknown $(P)$ of the reaction is

The major product $A$ is:

Answer the following questions:
$(i)$ What is the bond length of $C-C$,$C=C$,and $C\equiv C$?
$(ii)$ What will be the effect on bond length as bond multiplicity increases?
$(iii)$ What is the relation between reactivity of compound,bond strength and bond order between two carbon atoms?
$(iv)$ What is the rate of reaction of $Cl_2, Br_2,$ and $I_2$ with $CH_2=CH_2$?
$(v)$ What is the difference between $2-$butyne and $1-$butyne? By which test can we distinguish between these two?
$(vi)$ Which real product is obtained on hydrolysis of alkyne? Why?
$(vii)$ Give the structure and $IUPAC$ name:
$(a)$ Vinyl chloride
$(b)$ Vinyl cyanide
$(c)$ Glyoxal
$(d)$ Silver acetylide
$(e)$ Diacetyl
$(f)$ Glycol