Question

Identify alkane from the compounds given below.​

• A. $C_5{H}_7$
• B. $C_5{H}_{12}$
• C. $C_4{H}_8$
• D. $C_3{H}_4$

Answer 1

The correct option is B $C_5{H}_{12}$

Compound 1:
n = 5, substitute it into the general formula;
$C_n{H}_{2n+2}=C_5{H}_{12}$
Hence, it is an alkane.

Compound 2:
n = 4, substitute it into the general formula;
$C_n{H}_{2n+2}=C_4{H}_{10}\ne C_4{H}_8$
Hence, it is not an alkane.

Compound 3:
n = 3, substitute it into the general formula;
$C_n{H}_{2n+2}=C_3{H}_8\ne C_3{H}_4$
Hence, it is also not an alkane.

Compound 4:
n = 5, substitute it into the general formula;
$C_n{H}_{2n+2}=C_5{H}_{12}\ne C_5{H}_7$
Hence, it is also not an alkane.