A carbonyl compound with molecular mass 86, does not reduce Fehling's solution but forms crystalline bisulphite derivative and gives iodoform test. The possible compound is

Options

A. 2-pentanone and 3- pentanone
B. 2-pentanone and 3-methyl-2-butanone
C. 2-pentanone and pentanal
D. 3-pentanone and 3-methyl-2-butanone.

Explanation

To solve the problem, let's break it down step by step:

### Step 1: Analyze the Molecular Mass
The molecular mass of the carbonyl compound is given as 86 g/mol. This information helps us narrow down the possible carbonyl compounds.

**Hint:** Look for carbonyl compounds (aldehydes or ketones) that have a molecular mass close to 86 g/mol.

### Step 2: Identify the Type of Carbonyl Compound
The problem states that the compound does not reduce Fehling's solution. This indicates that the compound is not an aldehyde, as aldehydes typically reduce Fehling's solution. Therefore, we can conclude that the compound is a ketone.

**Hint:** Remember that only aldehydes can reduce Fehling's solution, while ketones do not.

### Step 3: Consider the Formation of Crystalline Bisulphite Derivative
The compound forms a crystalline bisulphite derivative. This property is characteristic of carbonyl compounds, particularly ketones, which can react with sodium bisulphite to form a solid derivative.

**Hint:** Look for ketones that readily form bisulphite derivatives.

### Step 4: Iodoform Test
The compound gives a positive iodoform test. This test is specific for methyl ketones or compounds that can be oxidized to methyl ketones. Therefore, the carbonyl compound must be a methyl ketone.

**Hint:** Recall that the iodoform test is positive for methyl ketones (RCOCH3) and some secondary alcohols.

### Step 5: Identify Possible Compounds
Now, we need to identify specific methyl ketones with a molecular mass of 86 g/mol. The two common methyl ketones that fit this description are:
1. 2-Pentanone (C5H10O)
2. 3-Methylbutan-2-one (C5H10O)

Both of these compounds have a molecular mass of 86 g/mol and are methyl ketones.

**Hint:** Check the molecular formulas of the identified compounds to confirm their molecular mass.

### Conclusion
Based on the analysis, the possible compounds that fit the criteria are 2-pentanone and 3-methylbutan-2-one.

**Final Answer:** The possible compound is 2-pentanone or 3-methylbutan-2-one.