Question

Choose the correct option

${\mathrm{C}}_5{\mathrm{H}}_{10}$ is an

• A. alkane
• B. alkene
• C. alkyne
• D. alkyl group

Answer 1

The correct option is B

alkene

Explanation for the correct option

(B) Alkene

Definition of IUPAC names

IUPAC nomenclature of organic chemistry is a method of naming organic chemical compounds as recommended by the International Union of Pure and Applied Chemistry.

• An alkene is a hydrocarbon containing a carbon-carbon double bond.
• Branched or unbranched hydrocarbons that have a general formula of ${\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2\mathrm{n}}$
• The probable structures for the ${\mathrm{C}}_5{\mathrm{H}}_{10}$can be :

Explanation for the incorrect option

(A) Alkane

• Compounds having carbon and hydrogen atoms with single covalent bonds
• The general formula for alkanes are ${\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2\mathrm{n}+2}$
• This means if 5 carbon are there, according to the formula there should be 12 hydrogens : ${\mathrm{C}}_5{\mathrm{H}}_{2\mathrm{x}5+2}$

(C) Alkyne

• Compounds having a carbon-carbon triple bond.
• The general formula for alkanes are ${\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2\mathrm{n}-2}$
• This means if 5 carbon is there, according to the formula there should be 8 hydrogens : ${\mathrm{C}}_5{\mathrm{H}}_{2\mathrm{x}5-2}$

(C) Alkyl

• an alkyl substituent is an alkane missing one hydrogen
• The general formula for alkanes are ${\mathrm{C}}_{\mathrm{n}}{\mathrm{H}}_{2\mathrm{n}+1}$
• This means if 5 carbon is there, according to the formula there should be 11 hydrogens : ${\mathrm{C}}_5{\mathrm{H}}_{2\mathrm{x}5+1}$

Therefore, ${\mathrm{C}}_5{\mathrm{H}}_{10}$is the formula for an alkene.