Final answer:
Diethyl ether's lower polarity and weaker intermolecular forces compared to isopropyl alcohol's ability to hydrogen bond explains why the reaction fails with diethyl ether; it has a higher vapor pressure, allowing molecules to escape more easily, disrupting necessary interactions for the reaction.
Step-by-step explanation:
The reaction in part A fails if diethyl ether is used instead of isopropyl alcohol because diethyl ether has a significantly different polarity and intermolecular forces (IMFs) compared to isopropyl alcohol. Diethyl ether is less polar than isopropyl alcohol, and it exhibits relatively weak dipole-dipole interactions, which means that its molecules can escape more readily from the liquid phase due to its higher vapor pressure. On the other hand, isopropyl alcohol can engage in strong hydrogen bonding due to the presence of an -OH (hydroxyl) group. These hydrogen bonds contribute to significantly stronger IMFs, which results in fewer molecules escaping from the liquid at any given temperature, consequently showing a lower vapor pressure than diethyl ether and making isopropyl alcohol a more suitable solvent in reactions where hydrogen bonding interactions are necessary for the reaction to proceed efficiently.