Question

How many primary alcoholic groups are present in glucose?

Hint:

In glucose, the –CH$_2$OH group at the end of the chain is the only primary alcohol; the rest are secondary alcohols.

Answer 1

Step 1: Structure of glucose.
Glucose is an aldohexose with the molecular formula C$_6$H$_{12}$O$_6$. Its open-chain structure is: \[ HOCH_2 – (CHOH)_4 – CHO \]
Step 2: Identify alcoholic groups.
- The four middle carbons each have a hydroxyl (–OH) group, making them secondary alcohols.
- The terminal –CH$_2$OH group at C-6 is a primary alcoholic group.

Step 3: Conclusion.
Thus, glucose has only one primary alcoholic group (at carbon-6).

Final Answer: \[ \boxed{\text{(A) One}} \]