Question

How many moles of acetic anhydride $\left(A{c}_{2}O\right)$ is needed to react completely with tartaric acid, ribose and glucose respectively?

• A. 2, 4 and 5
• B. 2, 3 and 4
• C. 4, 5 and 6
• D. 4, 5 and 5

Answer 1

The correct option is A 2, 4 and 5

2, 4 and 5 moles of acetic anhydride $\left(A{c}_{2}O\right)$ is required to react completely with tartaric acid, ribose and glucose respectively, as they contain 2, 4 and 5 free $-OH$ groups respectively.
The reaction follows as:
$R-OH+A{c}_{2}O\to R-OAc+AcOH$