A mixture when rubbed with dilute acid smells like vinegar. It contains salt of :

Options

A. sulphite
B. nitrate
C. nitrile
D. acetate

Answer

To determine which salt in the mixture produces a vinegar-like smell when rubbed with dilute acid, we can follow these steps:

### Step 1: Identify the salts in the mixture
The salts mentioned are:
- Sulphite
- Nitrate
- Nitrile
- Acetate

### Step 2: Recall the properties of each salt
- **Sulphite**: When reacted with dilute acid, it typically produces sulfur dioxide (SO2) gas, which has a pungent smell, not vinegar-like.
- **Nitrate**: Nitrates generally produce nitrogen oxides when reacted with dilute acids, which do not smell like vinegar.
- **Nitrile**: Nitriles do not produce a vinegar-like smell when reacted with dilute acids.
- **Acetate**: Acetate salts, when reacted with dilute acids, produce acetic acid (CH3COOH), which has a characteristic vinegar smell.

### Step 3: Conduct the reaction for acetate
Consider the example of lead acetate (Pb(CH3COO)2). When lead acetate is rubbed with dilute hydrochloric acid (HCl), the reaction is as follows:

\[ \text{Pb(CH}_3\text{COO)}_2 + 2 \text{HCl} \rightarrow \text{PbCl}_2 \downarrow + 2 \text{CH}_3\text{COOH} \]

This reaction produces lead chloride (PbCl2), which is a white precipitate, and acetic acid (CH3COOH), which is responsible for the vinegar smell.

### Step 4: Conclusion
Since the only salt that produces a vinegar-like smell when reacted with dilute acid is acetate, we conclude that the mixture contains salt of acetate.

### Final Answer
The mixture contains salt of **acetate**.

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