To determine whether two liquids are miscible, you need to consider their molecular structure and polarity.
Miscible liquids are able to mix together in all proportions, forming a homogenous solution. This occurs when the intermolecular forces between the molecules of the two liquids are similar enough to allow them to mix at the molecular level.
Here's how you can determine whether the given pairs of liquids are miscible:
1. H2O (water) and CH3CH2CH2CH2CH3 (pentane):
Water is a highly polar molecule due to its bent molecular structure and presence of oxygen, while pentane is a nonpolar molecule. Since polar and nonpolar molecules have different intermolecular forces, water and pentane are immiscible. They will not mix and will form distinct layers when combined.
2. C6H6 (benzene) and CCl4 (chloroform):
Both benzene and chloroform are nonpolar molecules. Since they have similar intermolecular forces, they are considered miscible. When mixed, benzene and chloroform will blend together to form a homogenous solution.
3. C2H5OH (ethanol) and CH3COOH (acetic acid):
Ethanol and acetic acid are both polar molecules, primarily due to the presence of the highly electronegative oxygen atom. However, acetic acid contains an additional polar functional group - the carbonyl (C=O) group. This makes acetic acid more polar than ethanol. As a result, ethanol and acetic acid are miscible and will mix together to form a homogenous solution.
In summary, the pair of liquids that will be miscible is C6H6 (benzene) and CCl4 (chloroform), while H2O (water) and CH3CH2CH2CH2CH3 (pentane) and C2H5OH (ethanol) and CH3COOH (acetic acid) are immiscible.