Question

linolenic acid is a polyunsaturated fatty acid with 18 carbons and three double bonds (18:3). find its molecular formula.
select the correct answer below:
○ c₁₈h₃₂o₂
○ c₁₈h₃₆o₂
○ c₁₈h₃₀o₂
○ c₁₈h₃₄o₂

Explanation:

Step1: Determine the formula for a saturated fatty acid

The general formula for a saturated fatty acid is \(C_nH_{2n}O_2\). For \(n = 18\) (18 carbons), the formula would be \(C_{18}H_{36}O_2\).

Step2: Adjust for unsaturation

Each double bond removes 2 hydrogen atoms. There are 3 double bonds. So we subtract \(2\times3 = 6\) hydrogen atoms from the saturated formula.
\(H\) atoms in unsaturated formula \(=36 - 6=30\)

Answer:

\(C_{18}H_{30}O_2\)