A cyanohydrin of a compound X on hydrolysis gives lactic acid. The X is

Options

A. `HCHO`
B. `CH_(3)CHO`
C. `(CH_(3))_(2)CO`
D. `C_(6)H_(5)CH_(2)CHO`

Explanation

To find the compound X that gives lactic acid upon hydrolysis of its cyanohydrin, we can follow these steps:

### Step 1: Identify Lactic Acid
Lactic acid is chemically known as 2-hydroxypropanoic acid. Its structure can be represented as:

```
OH
|
CH3-CH-COOH
```

This indicates that lactic acid has a hydroxyl (-OH) group and a carboxylic acid (-COOH) group on the second carbon of a three-carbon chain.

### Step 2: Understand Cyanohydrin Formation
Cyanohydrins are formed by the reaction of carbonyl compounds (aldehydes or ketones) with hydrogen cyanide (HCN). The general reaction can be represented as:

```
RCHO + HCN → RCH(OH)CN
```

Where RCHO is an aldehyde or ketone, and RCH(OH)CN is the resulting cyanohydrin.

### Step 3: Hydrolysis of Cyanohydrin
Upon hydrolysis, the cyanohydrin will convert to a carboxylic acid and ammonia. The reaction can be represented as:

```
RCH(OH)CN + H2O → RCH(OH)COOH + NH3
```

In our case, we want to find a cyanohydrin that, upon hydrolysis, gives lactic acid.

### Step 4: Determine the Structure of Compound X
From the structure of lactic acid, we can deduce that the cyanohydrin must have a structure that, when hydrolyzed, will yield the lactic acid structure.

If we consider the structure of lactic acid, we can deduce that the corresponding cyanohydrin must be:

```
OH
|
CH3-CH-CN
```

This suggests that compound X must be acetaldehyde (CH3CHO), which can react with HCN to form the cyanohydrin.

### Step 5: Conclusion
Thus, the compound X is acetaldehyde (CH3CHO). When acetaldehyde reacts with HCN, it forms the cyanohydrin, which upon hydrolysis gives lactic acid.

### Final Answer
The compound X is **acetaldehyde (CH3CHO)**.

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