Question

A hydrocarbon has three carbon atoms. Write down its molecular formula as an alkyne.

Answer 1

Solution:

1. Alkynes:

• Alkyne is a hydrocarbon having at least one triple bond between two carbon atoms.
• Its general formula is ${\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2\mathrm{n}-2}$, where ‘n’ is the number of carbon atoms.
• For example: ethyne, propyne, butyne having $2,3,4$ carbon atoms respectively are written as ${\mathrm{C}}_2{\mathrm{H}}_2$ ${\mathrm{C}}_3{\mathrm{H}}_4$ ${\mathrm{C}}_4{\mathrm{H}}_6$ so on

2. Determine the molecular formula of hydrocarbon as an alkyne that has three carbon atoms:

Since the hydrocarbon has three carbon atoms, thus, on substituting the value of$‘\mathrm{n}’$ as $3$ in the general formula of alkyne, we get the formula of the compound having three$\mathrm{C}$atoms, ${\mathrm{C}}_3{\mathrm{H}}_{2\times 3-2}={\mathrm{C}}_3{\mathrm{H}}_4$

Thus, the molecular formula as alkyne is ${\mathrm{C}}_3{\mathrm{H}}_4$