Which one of the following substances would be the most soluble in CCl4?

A) NaCl B) NH3 C) H2O D) C10H22 or E) CH3CH2OH

Working on the ‘like dissolves like’ approach…
CCl4 is not a polar molecule and nor is octane (C10H22) so they will produce a solution.
The other substances are either ionic (NaCl) or very polar (ammonia, water and ethanol) and so do not dissolve in CCl4 – but will mix with water, a polar solvent.

I would say C10H22; since it is the least polar molecule. CCl4 is non-polar; so it would be a good solvent for a non-polar solute.