Question

Which of the following compound is obtained when glucose is treated with dilute nitric acid?

• A. Glucose oxime
• B. Gluconic acid
• C. Saccharic acid
• D. Glucose cyanohydrin

Hint:

To remember the oxidation products of glucose easily, keep this summary in mind:

• Glucose + Bromine water ($\text{Br}_2/\text{H}_2\text{O}$) $\rightarrow$ Gluconic acid (Monocarboxylic acid)

• Glucose + Nitric acid ($\text{HNO}_3$) $\rightarrow$ Saccharic acid (Dicarboxylic acid)

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks for the organic product obtained when D-glucose is subjected to oxidation using a mild yet effective oxidizing acid like dilute nitric acid ($\text{HNO}_3$).

Step 2: Key Formula or Approach:
Glucose contains two types of oxidizable groups at its terminals: a primary aldehyde group (-CHO) at C1 and a primary alcohol group ($\text{-CH}_2\text{OH}$) at C6. While mild oxidizing agents like bromine water ($\text{Br}_2/\text{H}_2\text{O}$) selectively oxidize only the aldehyde to a carboxylic acid, a stronger oxidizing agent like dilute $\text{HNO}_3$ concurrently oxidizes both the terminal aldehyde and the primary alcohol groups into carboxylic acid groups (-COOH).

Step 3: Detailed Explanation:
1. The structural formula of glucose can be written as: $$\text{CHO}\mathrel{-}(\text{CHOH})_4\mathrel{-}\text{CH}_2\text{OH}$$ 2. When treated with dilute nitric acid ($\text{HNO}_3$), the aldehyde group (-CHO) at C1 is oxidized to a carboxylic acid group (-COOH).
3. Simultaneously, the primary alcohol group ($\text{-CH}_2\text{OH}$) at the other end (C6) is also oxidized to a carboxylic acid group (-COOH).
4. The resulting dicarboxylic acid has the structure: $$\text{COOH}\mathrel{-}(\text{CHOH})_4\mathrel{-}\text{COOH}$$ This specific six-carbon dicarboxylic acid is known as saccharic acid (or glucaric acid).

Step 4: Final Answer:
The compound obtained is saccharic acid, which corresponds to option (C).