$Crotonyl$ alcohol is an example of

Which of the following structures is an example of a symmetrical or simple ether?

How many sigma $(\sigma)$ bonds are in a molecule of diethyl ether,$C_2H_5OC_2H_5$?

Write structures of the compounds whose $IUPAC$ names are as follows:
$(i)$ $2-$Methylbutan$-2-$ol
$(ii)$ $1-$Phenylpropan$-2-$ol
$(iii)$ $3,5-$Dimethylhexane$-1,3,5-$triol
$(iv)$ $2,3-$Diethylphenol
$(v)$ $1-$Ethoxypropane
$(vi)$ $2-$Ethoxy$-3-$methylpentane
$(vii)$ Cyclohexylmethanol
$(viii)$ $3-$Cyclohexylpentan$-3-$ol
$(ix)$ Cyclopent$-3-$en$-1-$ol
$(x)$ $4-$Chloro$-3-$ethylbutan$-1-$ol.

The general molecular formula,which represents the homologous series of alkanols is

The total number of structural isomeric alcohols with the molecular formula $C_4H_{10}O$ is $:-$