Which of the following statement is not correct for Butan-2-ol?

It is optically inactive

The correct answer is Option (2) → It is optically inactive

Let’s analyze Butan-2-ol (CH₃–CH(OH)–CH₂–CH₃):

1. Stereocentre:
• The second carbon (C2) has four different groups: –OH, –CH₃, –CH₂CH₃, –H → one stereocentre 
2. Chirality:
• Presence of one stereocentre → molecule is chiral 
3. Optical activity:
• Pure enantiomer is optically active
• Racemic mixture (50:50) → optically inactive
4. Non-superimposable mirror images:
• True for chiral compounds