What is the product when glucose reacts with bromine water?
Gluconic acid
Understanding the Reaction of Glucose with Bromine Water
The question asks about the product formed when glucose reacts with bromine water. To understand this, we need to know the structure of glucose and the nature of bromine water.
Glucose is a monosaccharide, specifically an aldohexose. It contains an aldehyde group ($\text{-CHO}$) and multiple hydroxyl ($\text{-OH}$) groups. Bromine water ($\text{Br}_2\text{/H}_2\text{O}$) is a mild oxidizing agent.
Oxidation of Glucose by Bromine Water
Mild oxidizing agents like bromine water selectively oxidize the aldehyde group ($\text{-CHO}$) of aldoses (sugars with an aldehyde group) to a carboxylic acid group ($\text{-COOH}$). They typically do not oxidize the alcohol groups present in the molecule, especially secondary alcohol groups.
When glucose reacts with bromine water, the aldehyde group at carbon C-1 is oxidized. The resulting product is a carboxylic acid derived from glucose, where the aldehyde group has been converted to a carboxylic acid group.
The reaction can be represented simply as:
$\text{Glucose (Aldehyde group)} \quad \xrightarrow{\text{Br}_2\text{/H}_2\text{O}} \quad \text{Gluconic Acid (Carboxylic acid group)}$
Let's look at the options provided and see which one matches this description.
- Glyceraldehyde: This is a triose, a simple sugar with only three carbon atoms. It is not formed from glucose reaction.
- Gluconic acid: This is the carboxylic acid formed by the oxidation of the aldehyde group of glucose. This matches the expected product from the reaction of glucose with a mild oxidizing agent like bromine water.
- Saccharic acid: This acid is formed when glucose is oxidized by a strong oxidizing agent (like nitric acid), which oxidizes both the aldehyde group and the primary alcohol group ($\text{-CH}_2\text{OH}$) at the other end of the molecule to carboxylic acid groups. Bromine water is not a strong oxidizing agent and does not perform this reaction.
- Oxime: An oxime is formed when a compound containing an aldehyde or ketone group reacts with hydroxylamine ($\text{NH}_2\text{OH}$), not bromine water.
Therefore, the product when glucose reacts with bromine water is Gluconic acid.
| Oxidizing Agent | Functional Groups Attacked | Product Name | Type of Acid |
|---|---|---|---|
| Bromine Water ($\text{Br}_2\text{/H}_2\text{O}$) - Mild | Aldehyde ($\text{-CHO}$) | Gluconic Acid | Aldonic acid |
| Nitric Acid ($\text{HNO}_3$) - Strong | Aldehyde ($\text{-CHO}$) and Primary Alcohol ($\text{-CH}_2\text{OH}$) | Saccharic Acid (or Glucaric acid) | Aldaric acid (or Saccharic acid) |
Revision Table: Key Carbohydrate Reactions
| Reactant | Reagent | Product(s) | Reaction Type |
|---|---|---|---|
| Glucose | Bromine Water ($\text{Br}_2\text{/H}_2\text{O}$) | Gluconic Acid | Mild Oxidation |
| Glucose | Nitric Acid ($\text{HNO}_3$) | Saccharic Acid | Strong Oxidation |
| Glucose | Reducing agents (e.g., $\text{NaBH}_4$) | Sorbitol (Glucitol) | Reduction |
| Glucose | Hydroxylamine ($\text{NH}_2\text{OH}$) | Glucose Oxime | Addition-Elimination |
Additional Information: Aldonic Acids and Saccharic Acids
When an aldose is oxidized at the aldehyde group (C-1) by a mild oxidizing agent like bromine water, the product is called an aldonic acid. Gluconic acid is an example of an aldonic acid formed from glucose.
When an aldose is oxidized at both the aldehyde group (C-1) and the primary alcohol group (the last carbon, C-6 in glucose) by a strong oxidizing agent like nitric acid, the product is called an aldaric acid (also sometimes called saccharic acid, though this term can be less precise for general aldaric acids). Saccharic acid is the aldaric acid formed from glucose.
These oxidation reactions are important for characterizing carbohydrates and understanding their functional groups.
Important Questions from Organic Compounds Containing Nitrogen
The correct increasing order of basic strength of amine is:
(A) C₆H₅NH₂ < NH₃ < C₆H₅CH₂NH₂ < C₂H₅NH₂ < (C₂H₅)₂NH
(B) NH₃ < C₆H₅NH₂ < C₆H₅CH₂NH₂ < C₂H₅NH₂ < (C₂H₅)₂NH
(C) C₆H₅CH₂NH₂ < C₆H₅NH₂ < NH₃ < C₂H₅NH₂ < (C₂H₅)₂NH
(D) C₂H₅NH₂ < (C₂H₅)₂NH < C₆H₅NH₂ < NH₃
(E) NH₃ < C₂H₅NH₂ < C₆H₅CH₂NH₂ < (C₂H₅)₂NH < C₆H₅NH₂
Choose the correct answer from the options given below:
In which of the following molecules carbon atom marked with asterisk (*) is a stereocentre or chiral centre?
Match List-I with List-II:
List-I List-II (A) Urease (I) Maltose (B) Maltase (II) Glucose and fructose (C) Invertase (III) NH₃ and CO₂ (D) Diastase (IV) Glucose Choose the correct answer from the options given below:
Phenol is manufactured from hydrocarbon, Cumene. Cumene is chemically:
t99.9% with respect to t90% for a first-order reaction is:
