In the compound $^1CH_2 = ^2CH - ^3CH_2 - ^4CH_2 - ^5C \equiv ^6CH$, the $C_2 - C_3$ bond is of which type?

Allyl isocyanide contains $......... \sigma$ and $......... \pi$ bonds.

The compounds containing $sp$-hybridised carbon atom are:
$(I)$ $H_3C-N(CH_3)-CHO$
$(II)$ Pyridine
$(III)$ $H_3C-CN$
$(IV)$ $H_2C=C=CH-CH_3$

The structural formula of a compound is $CH_3 - CH = C = CH_2$. The type of hybridization at the four carbons from left to right are

Consider a positively charged $C_2H_3$ species in which the positively charged carbon is $sp$-hybridized,the uncharged carbon is $sp^2$-hybridized and an empty $p$-orbital is perpendicular to the $\pi$ system. What is the best description of this cation?

In which of the following species is the underlined carbon having $sp^3$ hybridisation?