D. The number increases and then decreases for noble gases
Explanation:
It is often desirable to determine the mass percent of elements in a given compound.
To determine the mass percent of elements:
- Evaluate the formula mass of the compound. This is done by summing the atomic masses of the atoms in the compound together.
- The mass percentage is determined by pacing the mass contribution of each element or group to the formula mass of the compound and multiply by 100.
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Liter measures liquid- so a measuring cup
Structure along with ¹H-NMR is shown below.
Signal for Hₐ; Based on multiplicity of of the peak, a
Singlet peak (the only singlet peak present in spectrum) at
2.2 ppm was assigned to Hₐ. As the methyl group in not coupling with any other proton so it gave a singlet peak.
Signal for Hb; Based on multiplicity of of the peak, a
Quartet peak (the only quartet peak present in spectrum) at
2.4 ppm was assigned to Hb. As the methylene group in coupling with methyl group having three protons so it gave a Quartet peak.
Signal for Hc; Based on multiplicity of of the peak, a
Triplet peak (the only triplet peak present in spectrum) at
1.1 ppm was assigned to Hc. As the methyle group in coupling with methylene group having two protons so it gave a Triplet peak.