Question

At least one carbon bond in unsaturated hydrocarbon is ________

Answer 1

Hint: Here we will study about hydrocarbons. We have to know about the unsaturated hydrocarbons and their properties. Carbon can form single bond, double bond and triple bond with other carbon atoms depending on the remaining valency of electrons.

Complete answer:
Hydrocarbons are those compounds which contain hydrogen and carbon atoms. Hydrocarbon can be classified into two categories based on the type of bonding carbon-carbon make in a chain,
\[(i)\] Saturated Hydrocarbons: The hydrocarbons which contain only a single bond between carbon-carbon atoms are known as saturated hydrocarbons. These hydrocarbons are healthy for consumption. The general formula for these hydrocarbons is \[{C_n}{H_{2n + 2}}\]. Here n is an integer starting from one.
For example: n-butane\[\left( {C{H_3} - C{H_2} - C{H_2} - C{H_3}} \right)\]
\[(ii)\]Unsaturated Hydrocarbons: The hydrocarbons which contain double or triple bonds between carbon-carbon atoms are known as unsaturated hydrocarbons. These hydrocarbons are unhealthy for consumption. These are also called fats. Therefore we can say that fats contain unsaturated hydrocarbons. The general formula for compounds containing double bond is \[{C_n}{H_{2n}}\] whereas for hydrocarbons containing triple bond is \[{C_n}{H_{2n - 2}}\]. Here n is an integer starting from one.
For example: But-2-ene\[\left( {C{H_3} - CH = CH - C{H_3}} \right)\] , But-2-yne \[\left( {C{H_3} - C \equiv C - C{H_3}} \right)\]
Thus we can say that in unsaturated hydrocarbons there must be at least one double bond.

Note:
Hydrocarbons may contain both double bond and triple bond. These hydrocarbons are also known as unsaturated hydrocarbons. The higher the value of unsaturation in a compound, the more hazardous it is for consumption. The enthalpy of hydrogenation for unsaturated hydrocarbons is much more than that of saturated hydrocarbons. Unsaturated hydrocarbons undergo addition reactions while saturated hydrocarbons do not undergo addition reactions.