Chapter 12C.8, Problem 21P

Identify A and B, isomers of molecular formula ${\text{C}}_{\text{3}}{\text{H}}_{\text{4}}{\text{Cl}}_{\text{2}}$, from the given ${}^{\text{1}}\text{H}$ NMR data: Compound A exhibits signals at $1.75\left(\text{doublet, 3H, }J=\text{6}\text{.9 Hz}\right)$ and $5.89\left(\text{quartet, 1H, }J=\text{6}\text{.9 Hz}\right)\text{ppm}$. Compound B exhibits signals at $4.16\left(\text{singlet, 2H}\right),5.42\left(\text{doublet, 1H, }J=1.\text{9 Hz}\right)$, and $5.59\left(\text{doublet, 1H, }J=1.\text{9 Hz}\right)\text{ppm}$.