Which the one of the following is first member of monosaccharides ?

Options

A. `CH_2OH-overset(O)overset(||)C-CH_2OH`
B. `HOCH_2-CHOH-CHO`
C. `HOCH_2-CHOH-CHOH-CHO`
D. `HOCH_2-CHOH- overset(O)overset(||)C-CH_2OH`

Answer

To solve the question "Which one of the following is the first member of monosaccharides?", we can follow these steps:

### Step 1: Understand Monosaccharides
Monosaccharides are the simplest form of carbohydrates and cannot be hydrolyzed into simpler sugars. They have the general formula (CH2O)n, where n is typically between 3 and 7.

### Step 2: Identify the First Member
The first member of monosaccharides is the one with the smallest number of carbon atoms. The simplest monosaccharide is glyceraldehyde, which has three carbon atoms.

### Step 3: Write the Structure of Glyceraldehyde
The structure of glyceraldehyde can be represented as follows:
- It contains three carbon atoms (C).
- The molecular formula is C3H6O3.
- The structure can be depicted as:
- CH2OH (the aldehyde group)
- CHO (the carbonyl group)
- CH2OH (the hydroxymethyl group)

### Step 4: Confirm the Correct Answer
From the provided options, we need to identify which option corresponds to glyceraldehyde. If option B lists glyceraldehyde or its molecular formula (C3H6O3), then option B is the correct answer.

### Conclusion
Thus, the first member of monosaccharides is glyceraldehyde, and the correct answer is option B.

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