Question

IUPAC name of is

• A. But-2-ene-2,3-diol
• B. Pent-2-ene-2,3-diol
• C. 2-Methylbut-2-ene-2,3-diol
• D. Pent-3-ene-3,4-diol

Answer 1

The correct option is B Pent-2-ene-2,3-diol

According to IUPAC, the correct numbering of the following compound is:The parent chain is of five carbon so word root is pent.
Double bond is present 2nd position. suffix used for double bond is 'ene'.
Alcohol group $(-OH)$ is present as a substituent at position 2 and 3. suffix used for alcohol group $(-OH)$ is 'ol'.
$(-OH)$ group is preffered over double bond according to IUPAC.
Hence, the correct IUPAC name is Pent-2-ene-2,3-diol