Nitrating mixture is

Options

A. Fuming nitric acid
B. mixture of conc. `H_(2)SO_(4)` and conc. `HNO_(3)`
C. Mixture of nitric acid and anhydrous zinc chloride
D. None of these

Answer

To determine what a nitrating mixture is, we can follow these steps:

### Step 1: Define Nitrating Mixture
A nitrating mixture is a specific combination of chemicals used in the nitration reaction, which is a type of electrophilic substitution reaction.

**Hint:** Recall that nitration involves the introduction of a nitro group (-NO2) into an organic compound.

### Step 2: Identify the Components
The nitrating mixture consists of concentrated sulfuric acid (H2SO4) and concentrated nitric acid (HNO3).

**Hint:** Think about the properties of these acids and why they are used together in nitration.

### Step 3: Understand the Role of Sulfuric Acid
Concentrated sulfuric acid acts as a stronger acid compared to nitric acid. It provides protons (H+) and bisulfate ions (HSO4-).

**Hint:** Consider how the strength of an acid can influence the reactivity of other substances in a mixture.

### Step 4: Reaction Mechanism
When sulfuric acid donates a proton (H+) to nitric acid, it facilitates the formation of the nitronium ion (NO2+), which is the active electrophile in the nitration process.

**Hint:** Remember that electrophiles are species that seek electrons and can react with nucleophiles in organic reactions.

### Step 5: Formation of the Electrophile
The reaction between sulfuric acid and nitric acid leads to the formation of the nitronium ion (NO2+) after the removal of a water molecule.

**Hint:** Think about how the removal of water can drive the formation of a more stable product in chemical reactions.

### Conclusion
Thus, the nitrating mixture is defined as a mixture of concentrated sulfuric acid and concentrated nitric acid, which is used to generate the nitronium ion for nitration reactions.

**Final Answer:** The nitrating mixture is a mixture of concentrated sulfuric acid and concentrated nitric acid.

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