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

(N/A) $(i)$ $C-C = 154 \text{ pm}$,$C=C = 134 \text{ pm}$,$C\equiv C = 120 \text{ pm}$.
$(ii)$ Bond length decreases as bond multiplicity increases.
$(iii)$ Bond strength $\propto$ Bond order. Reactivity: $C\equiv C > C=C > C-C$ (for addition reactions).
$(iv)$ $Cl_2 > Br_2 > I_2$.
$(v)$ $1-$butyne is a terminal alkyne with an acidic $H$,while $2-$butyne is a non-terminal alkyne. They can be distinguished using $\text{Tollen's reagent}$ (ammoniacal silver nitrate).
$(vi)$ Carbonyl compounds (aldehydes or ketones) are obtained due to enol-keto tautomerism of the unstable enol intermediate.
$(vii)$
| Name | $IUPAC$ Name | Structure |
| :--- | :--- | :--- |
| Vinyl chloride | Chloroethene | $CH_2=CHCl$ |
| Vinyl cyanide | Prop$-2-$enenitrile | $CH_2=CHCN$ |
| Glyoxal | Ethanedial | $CHO-CHO$ |
| Silver acetylide | Silver ethynide | $Ag-C\equiv C-Ag$ |
| Diacetyl | Butane$-2,3-$dione | $CH_3-CO-CO-CH_3$ |
| Glycol | Ethane$-1,2-$diol | $HO-CH_2-CH_2-OH$ |