Question

question 2
which liquid had the weakest intermolecular attractive forces?
acetone (ch₃coch₃)
ethanol (ch₃oh)
water (h₂o)

Explanation:

To determine the liquid with the weakest intermolecular attractive forces, we analyze the intermolecular forces (IMFs) of each substance:

1. Acetone (\(\ce{CH3COCH3}\)): It has dipole - dipole interactions (from the polar carbonyl group, \(\ce{C = O}\)) and London dispersion forces. It does not have hydrogen bonding because there are no \(\ce{H}\) atoms bonded to \(\ce{N}\), \(\ce{O}\), or \(\ce{F}\) (the \(\ce{H}\) atoms in acetone are bonded to \(\ce{C}\)).

1. Ethanol (\(\ce{CH3OH}\)): It has hydrogen bonding (due to the \(\ce{O - H}\) bond), dipole - dipole interactions, and London dispersion forces. Hydrogen bonding is a relatively strong IMF.

1. Water (\(\ce{H2O}\)): It has extensive hydrogen bonding (two \(\ce{O - H}\) bonds per molecule), along with dipole - dipole and London dispersion forces. Water’s hydrogen bonding is very strong, making its IMFs stronger than those of ethanol in most cases and much stronger than acetone’s.

Since acetone only has dipole - dipole and London dispersion forces (while ethanol and water have hydrogen bonding, a stronger IMF), acetone has the weakest intermolecular attractive forces among the three.

Answer:

A. acetone (\(\ce{CH3COCH3}\))