Question

The type(s) of chemically non-equivalent protons present in the following molecule is _ _ _. (answer in integer)

Hint:

While counting chemically non-equivalent protons, first identify symmetry-related groupsSymmetry-related protons give the same NMR signal

Answer 1

Correct Answer: 2

Step 1: Identify the structure.
The given molecule is a substituted cubane derivativeIt contains methyl groups and ring hydrogens attached to the cubane framework

Step 2: Identify different proton environments.
There are two main types of protons present in the molecule: protons of the methyl groups and protons directly attached to the cubane ring carbons

Step 3: Check equivalence of methyl protons.
Due to symmetry in the molecule, all methyl groups are chemically equivalentTherefore, all methyl protons give one type of signal

Step 4: Check equivalence of ring hydrogens.
The hydrogens attached directly to the cubane skeleton are also related by symmetryHence, they are chemically equivalent to each other

Step 5: Count chemically non-equivalent proton types.
One type corresponds to methyl protons and one type corresponds to cubane ring protons

Step 6: Conclusion.
Thus, total number of chemically non-equivalent proton types is
\[ \boxed{2} \]