Final answer:
CCl4 (carbon tetrachloride) is the compound least likely to dissolve in water because it is a nonpolar molecule that cannot form hydrogen bonds with water.
Step-by-step explanation:
The solubility of a substance in water depends on its capacity to form hydrogen bonds with water molecules and its overall polarity. CCl4 (carbon tetrachloride) is a nonpolar molecule without any hydrogen atoms to form hydrogen bonds. Consequently, it is the substance least likely to dissolve in water compared to the others listed. On the other hand, substances like CH3(CH2)8CH2OH and CH3(CH2)9CHOH have long hydrocarbon chains that reduce solubility but also contain hydroxyl groups (-OH) which can form hydrogen bonds with water, making them somewhat soluble. CHCl3 (chloroform) has limited solubility due to its polar bonds and ability to participate in hydrogen bonding to a lesser extent. HOCH2CH2OH (ethylene glycol) is highly soluble in water due to its two hydroxyl groups allowing for extensive hydrogen bonding.