Question

The proton NMR spectrum in Figure $19.40$is for a compound having an empirical formula ${\mathrm{C}}_4{\mathrm{H}}_7{\mathrm{BrO}}_2$Identify the compound.

Short answer

The compound is${\mathrm{CH}}_3-{\mathrm{CH}}_2-\mathrm{CHBr}-\mathrm{COOH}$.

Step-by-step solution

Existence of triplet and quadrat

The spectrum indicates that the existence of four kinds of protons.

Existence of triplet at $\delta =1.0$shows the presence of a proton adjacent to methylene collection.

The existence of quadrat at$\delta =2.1$suggest the presence of methylene collection in between two various proton environment.

Existence of triplet and singlet

Existence of triplet at $\delta =4.3$shows the presence of $-{\mathrm{CH}}_3$collection adjacent to $-{\mathrm{CH}}_2$group.

Presence of singlet at $\delta =11$shows the existence of a $-\mathrm{OH}$group proton.

Conclusion

The above statement denotes that the compound is${\mathrm{CH}}_3-{\mathrm{CH}}_2-\mathrm{CHBr}-\mathrm{COOH}$.