Which among the following are unsaturated hydrocarbons?
$(i)$ $H_3C-CH_2-CH_2-CH_3$
$(ii)$ $H_3C-C\equiv C-CH_3$
$(iii)$ $H_3C-CH(CH_3)-CH_3$
$(iv)$ $H_3C-C(CH_3)=CH_2$

Which of the following functional groups is present in aldehyde compounds?

Define the term 'structural isomerism'. Explain why propane cannot exhibit this property. Draw the structures of possible isomers of butane,$C_{4}H_{10}$.

An organic compound $A$ of molecular formula $C_{2}H_{4}$ on reduction gives another compound $B$ of molecular formula $C_{2}H_{6}$. $B$ on reaction with chlorine in the presence of sunlight gives $C$ of molecular formula $C_{2}H_{5}Cl$.
$(a)$ Name the compounds $A, B$ and $C$.
$(b)$ Write the chemical equation for the conversion of $A$ to $B$ and name the type of reaction.

Carbon forms four covalent bonds by sharing its four valence electrons with four univalent atoms,e.g.,hydrogen. After the formation of four bonds,carbon attains the electronic configuration of:

What is the molecular formula of ethyl acetate?