In order to predict which of the choices would dissolve more in water as a solvent, let's examine the properties of the solvent. Water has a chemical formula of H₂O. In other ways, it could also be written as H-OH. Thus, water contains a hydrogen bond. This type of bond is existing for compounds having functional groups of -OH. -NH and -HF. So, if another solute having a hydrogen bond is allowed to dissolve in water, it would completely disappear into a solution.
Another famous property of water is its polarity. This property arises when there is an imbalance in the pull of electrostatic forces between individual atoms. As a result, it creates a dipole moment. In chemistry, the primary rule of solubility is that 'like dissolves like'. This means that polar solutes will dissolve in polar solvents. Similarly, nonpolar solutes will dissolve in nonpolar solvents. So, between polar CH₃OH and nonpolar CH₃(CH₂)₄CH₃, the CH₃OH will dissolve and form an aqueous solution. The CH₃(CH₂)₄CH₃ will not dissolve and will just settle down.
On the other example, KF is a polar compound while CO₂ is nonpolar. Hence, KF will form an aqueous solution with water. CO₂, in room temperature, is a gas. So, it will just escape from water and form a three-phase system: CO₂ being in the vapor phase, liquid water, and water vapor also in the vapor phase.
