The state of hybridisation of $C_2, C_3, C_5$ and $C_6$ of the hydrocarbon $CH_3-C_6(CH_3)_2-C_5H=C_4H-C_3H(CH_3)-C_2 \equiv C_1H$ is in the following sequence:

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

When petroleum is heated,the vapours contain mainly:

Write the main product of the given reactions:
$(1)$ $C_6H_5CH = CH_2 \xrightarrow{HBr}$
$(2)$ $C_4H_{10} \xrightarrow{\text{air}, \Delta}$

The major product $[C]$ of the following reaction sequence will be

Arrange the stability of the given gem-diols in decreasing order:
$I$: Cyclopropane$-1,1-$diol
$II$: Cyclobutane$-1,1-$diol
$III$: Cyclopentane$-1,1-$diol