Question

Identify D in the following sequence of reactions:

• A. n-propyl alcohol
• B. isopropyl alcohol
• C. propanal
• D. propionic acid

Answer 1

Answer: (A)

n-propyl alcohol

Answer 2

This reaction sequence involves several steps:
1. Formation of A (Grignard Reagent): Ethanol reacts with red phosphorus and iodine to form ethyl iodide which then reacts with magnesium in dry ether to form ethyl magnesium iodide (A). This is a Grignard Reagent which is very reactive.
2. Formation of B (Addition to Aldehyde) : Ethylmagnesium iodide (A) reacts with formaldehyde (HCHO) to form a magnesium alkoxide intermediate (B). This addition reaction results in an increase in the carbon chain.
3. Formation of C (Acidification): Acidification of (B) leads to the protonation of the alkoxide intermediate which yields propanol(C).
4. Formation of D: No further reaction occurs as we get propan-1-ol (n-propyl alcohol).
Conclusion: The major product D is n-propyl alcohol.