Question

Tautomerism will be exhibited by

• A. $(CH_3)_3 CNO$
• B. $(CH_3)_2NH$
• C. $R_3CNO_2$
• D. $RCH_2NO_2$

Answer 1

The Correct Option is D

To determine which compound exhibits tautomerism, let's first understand the concept of tautomerism. Tautomerism is a form of isomerism where compounds exist in rapidly interconvertible forms. This typically involves the transfer of a hydrogen atom and a switch of a single bond and adjacent double bond.

The question provides the following options:

1. (CH_3)_3 CNO
2. (CH_3)_2NH
3. R_3CNO_2
4. RCH_2NO_2

Let's evaluate each option:

• (CH_3)_3CNO: This compound does not have a hydrogen atom attached to the nitrogen, meaning it cannot undergo tautomerism.
• (CH_3)_2NH: This is an amine and lacks the structural requirements necessary for tautomerism, such as a carbonyl group (C=O) or nitro group (NO₂).
• R_3CNO_2: This compound contains a nitro group. However, there are no hydrogen atoms adjacent to the nitro group, which are necessary for tautomerism via proton transfer.
• RCH_2NO_2: This is a typical structure observed in keto-enol tautomerism involving a nitro group. Nitroalkanes like RCH_2NO_2 can undergo tautomerism as they have acidic hydrogen atoms adjacent to the nitro group, leading to tautomeric forms.

Thus, the correct answer is RCH_2NO_2 because it has the necessary structural components for tautomerism, specifically a hydrogen atom on a carbon adjacent to the nitro group.

Conclusion: The compound RCH_2NO_2 will exhibit tautomerism as it fulfills the structural requirement for such isomerism, in contrast to the other options provided.