Compound A, ${\mathbf{C}}_8{\mathbf{H}}_{\mathbf{1}0}\mathbf{O}$, has the IR and ${}^{\mathbf{1}}\mathbf{H}$NMR spectra shown. Proposea structure consistent with the observed spectra, and label each peak inthe NMR spectrum. Note that the absorption at $\mathbf{5}\mathbf{.}\mathbf{5}\mathbf{\delta }$disappears when ${\mathbf{D}}_{\mathbf{2}}\mathbf{O}$is added.

The formula ${\text{C}}_8{\mathrm{H}}_{10}\mathrm{O}$shows that the carbon present in molecule are 8 and we know in alkane the number of hydrogen are twice the number of carbon plus 2. The number of hydrogen here would have been 18 in case of alkane. So the multiple bonds present are 4. Indicating ring may also be present.

Given table has values for absorption of radiation at particular wavelength by specific functional group:

Functional group absorption band

From table and molecular formula it can be concluded:

• The broad peak at indicates a hydroxyl group.
• The peak at $1500\text{and 1600}{\mathrm{cm}}^{-1}$must be due to aromatic ring.
• The absorption at $\text{830}{\mathrm{cm}}^{-1}$shows ring is$\mathrm{p}\text{- disubstituted.}$

Single peak indicates no neighbor H atom is present to hydrogen. If peak splits into two it indicates only one neighbor H is present and if into three then two neighbor H are present and if four peaks then four neighbor hydrogens and so on.

Given table has values forchemical shift:

Chemical shift

From table, molecular formula and IR spectrum, it can be concluded:

From above data it can be concluded that below given structure is correct structure of given molecule, ${\mathrm{C}}_8{\mathrm{H}}_{10}\mathrm{O}$

In graph:

The peak at 5.5 shows OH group