Answer:

1,3,5-tri-isopropylbenzene is a compound with three isopropyl groups attached to a benzene ring. In the 1H NMR spectrum of this compound, the peaks arise from the different hydrogen atoms in the molecule.

Explanation:

1. Hydrogen atoms in the benzene ring:
The benzene ring in 1,3,5-tri-isopropylbenzene has six hydrogen atoms. These hydrogen atoms are all equivalent due to the symmetry of the benzene ring. Therefore, they will give rise to a single multiplet peak in the NMR spectrum.

2. Hydrogen atoms in the isopropyl groups:
Each isopropyl group in 1,3,5-tri-isopropylbenzene contains three hydrogen atoms. However, these three hydrogen atoms are not equivalent due to the presence of neighboring carbon atoms and the different chemical environment. Therefore, they will give rise to separate peaks in the NMR spectrum.

Combining the peaks:
Since there are three isopropyl groups in 1,3,5-tri-isopropylbenzene, there will be three sets of peaks corresponding to the hydrogen atoms in each isopropyl group. Each set will consist of three separate peaks due to the non-equivalence of the hydrogen atoms in the isopropyl group.

Total number of multiplet peaks:
Considering the peaks from the benzene ring and the isopropyl groups, there will be two sets of multiplet peaks in the 1H NMR spectrum of 1,3,5-tri-isopropylbenzene. Each set will consist of three separate peaks, resulting in a total of six peaks in the spectrum.

Therefore, the correct answer is '2 to 2', indicating that there will be two sets of multiplet peaks in the 1H NMR spectrum of 1,3,5-tri-isopropylbenzene.