The number of hydroxyl groups in glycerol (C₃H₈O₃) is x.

Solution

Chemistry ma’am · 3 steps

Read the IUPAC name, propane-1,2,3-triol: triol means three OH groups, one on each carbon.

1. Name the compound. Glycerol is propane-1,2,3-triol. The suffix "triol" means three -OH groups, and the locants 1, 2, 3 put one on each carbon of the propane chain.

   HO-CH₂-CH(OH)-CH₂-OH

2. Check the formula. Count atoms in this structure: 3 C, 3 O and 2 + 1 + 2 + 3 = 8 H. That matches C₃H₈O₃, and every O is in an -OH group.
3. So. Glycerol has 3 hydroxyl groups, so x = 3.

The common slip: 2. Confusing glycerol with glycol (ethane-1,2-diol) gives 2. Glycol is a diol, glycerol is a triol.

The idea to keep. The suffix tells you how many OH groups there are: -ol is one, -diol is two (glycol), -triol is three (glycerol). Check the count against the molecular formula.

Answer from the NTA final answer key. Solution by PrepWiser.