The types of hybridization present in $1, 2-$butadiene are

Which of the following does not contain an $sp^2$ hybridized carbon?

The hybridisations of carbon-$2$ in $P$ and $Q$ are respectively:

$(a)$ Discuss the concept of hybridization. What are its different types in a carbon atom.
$(b)$ What is the type of hybridization of carbon atoms marked with a star in the following structures:
$(a)$ $\overset{*}{C}H_2 = CH - C(=O)OH$
$(b)$ $CH_3 - \overset{*}{C}H_2 - OH$
$(c)$ $CH_3 - CH_2 - \overset{*}{C}H = O$
$(d)$ $\overset{*}{C}H_3 - CH = CH - CH_3$
$(e)$ $CH_3 - \overset{*}{C} \equiv CH$

Which of the following represents the given mode of hybridisation $sp^2-sp^2-sp-sp$ from left to right?

The total number of $\pi-$bond electrons in the following structure is