Calculate the index of hydrogen deficiency of these compounds. (a) Aspirin, \(\mathrm{C}_{9} \mathrm{H}_{8} \mathrm{O}_{4}\) (b) Ascorbic acid (vitamin \(\mathrm{C}\) ), \(\mathrm{C}_{6} \mathrm{H}_{g} \mathrm{O}_{6}\) (c) Pyridine, \(\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{~N}\) (d) Urea, \(\mathrm{CH}_{4} \mathrm{~N}_{2} \mathrm{O}\) (e) Cholesterol, \(\mathrm{C}_{2} \mathrm{H}_{45} \mathrm{O}\) (f) Dopamine, \(\mathrm{C}_{8} \mathrm{H}_{11} \mathrm{NO}_{2}\)

Short Answer

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a) Aspirin b) Ascorbic acid c) Pyridine d) Urea e) Cholesterol f) Dopamine Answer: a) Aspirin: IHD = 10 b) Ascorbic acid: IHD = 6 c) Pyridine: IHD = 6 d) Urea: IHD = 2 e) Cholesterol: IHD = 28 f) Dopamine: IHD = 8.5

Step by step solution

01

Find the number of carbon, hydrogen, and other atoms.

In aspirin, there are 9 carbons (n=9), 8 hydrogens (H=8), and 4 oxygen atoms. No other atoms are present.
02

Use the IHD formula.

Using the formula, we get: \(IHD = \frac{2(9) + 2 - 8 + 0 - 0}{2} = \frac{20}{2} = 10\). #a) Aspirin: IHD = 10# #b) Ascorbic acid: C6H9O6#
03

Find the number of atoms.

In ascorbic acid, there are 6 carbons (n=6), 8 hydrogens (H=8), and 6 oxygen atoms. No other atoms are present.
04

Use the IHD formula.

Using the formula, we get: \(IHD = \frac{2(6) + 2 - 8 + 0 - 0}{2} = \frac{12}{2} = 6\). #b) Ascorbic acid: IHD = 6# #c) Pyridine: C5H5N#
05

Find the number of atoms.

In pyridine, there are 5 carbons (n=5), 5 hydrogens (H=5), and 1 nitrogen atom(N=1).
06

Use the IHD formula.

Using the formula, we get: \(IHD = \frac{2(5) + 2 - 5 + 0 + 1}{2} = \frac{12}{2} = 6\). #c) Pyridine: IHD = 6# #d) Urea: CH4N2O#
07

Find the number of atoms.

In urea, there is 1 carbon (n=1), 4 hydrogens (H=4), 2 nitrogen atoms (N=2), and 1 oxygen atom.
08

Use the IHD formula.

Using the formula, we get: \(IHD = \frac{2(1) + 2 - 4 + 0 + 2}{2} = \frac{4}{2} = 2\). #d) Urea: IHD = 2# #e) Cholesterol: C27H45O#
09

Find the number of atoms.

In cholesterol, there are 27 carbons (n=27), 45 hydrogens (H=45), and 1 oxygen atom. No other atoms are present.
10

Use the IHD formula.

Using the formula, we get: \(IHD = \frac{2(27) + 2 - 45 + 0 - 0}{2} = \frac{56}{2} = 28\). #e) Cholesterol: IHD = 28# #f) Dopamine: C8H11NO2#
11

Find the number of atoms.

In dopamine, there are 8 carbons (n=8), 11 hydrogens (H=11), 1 nitrogen atom (N=1), and 2 oxygen atoms.
12

Use the IHD formula.

Using the formula, we get: \(IHD = \frac{2(8) + 2 - 11 + 0 + 1}{2} = \frac{17}{2} = 8.5\). #f) Dopamine: IHD = 8.5# #a) Aspirin: IHD = 10 #b) Ascorbic acid: IHD = 6 #c) Pyridine: IHD = 6 #d) Urea: IHD = 2 #e) Cholesterol: IHD = 28 #f) Dopamine: IHD = 8.5

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Most popular questions from this chapter

When placed in a powerful magnetic field, there is a small population bias for the \({ }^{1} \mathrm{H}\) and \({ }^{13} \mathrm{C}\) nuclei to be aligned with the magnetic field, and they precess.

According to the \((n+1)\) rule, if a hydrogen has \(n\) hydrogens nonequivalent to it but equivalent among themselves on the same or adjacent atom(s), its \({ }^{1} \mathrm{H}-\mathrm{NMR}\) signal will be split into \((n+1)\) peaks. \- Splitting patterns are commonly referred to as singlets (s), doublets (d), triplets \((t)\), quartets \((q)\), quintets, and multiplets ( \(m\) ). \- The relative intensities of peaks in a multiplet can be predicted from an analysis of spin combinations for adjacent hydrogens or from the mnemonic device called Pascal's triangle. \- A coupling constant \((J)\) is the distance between adjacent peaks in a multiplet and is reported in hertz \((\mathrm{Hz})\). The value of \(J\) depends only on internal fields within a molecule and is independent of the spectrometer field.

When a hydrogen nucleus is coupled to more than one set of adjacent hydrogen nuclei, the couplings combine. \- In the general case, if a hydrogen nucleus is coupled to a set of \(n\) hydrogen nuclei on one side and a set of \(m\) hydrogen nuclei on the other, the signal will be split into a maximum of \((n+1)(m+1)\) peaks. \- In molecules that are rigid, for example alkenes or cyclic molecules, all the \((n+1)(m+1)\) peaks can often be seen. \- However, because coupling constants can be similar, especially in flexible molecules, this splitting can simplify to a number of observed peaks that is equal to the number of adjacent H atoms \(A 1\), regardless of patterns of equivalence.

Compound M, molecular formula \(\mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}\), readily decolorizes \(\mathrm{Br}_{2}\) in \(\mathrm{CCl}_{4}\) and is converted by \(\mathrm{H}_{2} / \mathrm{Ni}\) into compound \(\mathrm{N}\), molecular formula \(\mathrm{C}_{3} \mathrm{H}_{12} \mathrm{O}\). Following is the \({ }^{1} \mathrm{H}-\mathrm{NMR}\) spectrum of compound \(\mathrm{M}\). The \({ }^{19} \mathrm{C}-\mathrm{NMR}\) spectrum of compound \(\mathrm{M}\) shows signals at \(\delta 146.12,110.75,71.05\), and \(29.88\). Deduce the structural formulas of compounds \(M\) and N.

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