Question

which of the following liquid pairs would be miscible? i. toluene (c₇h₈) and xylene (c₈h₁₀) ii. water and ethanol (c₂h₅oh) iii. water and xylene (c₈h₁₀)

Answer 1

Toluene and xylene are miscible due to their nonpolar structures; water and ethanol are miscible because ethanol can form hydrogen bonds with water, while water and xylene are immiscible because water is polar and xylene is nonpolar.

Step-by-step explanation:

The question asks which of the following liquid pairs would be miscible: i. toluene (C₇H₈) and xylene (C₈H₁₀), ii. water and ethanol (C₂H₅OH), iii. water and xylene (C₈H₁₀). The concept of miscibility refers to the ability of two substances to mix in any proportion without separating into two phases.

Toluene (C₆H₅-CH₃) and xylene are both nonpolar solvents with similar chemical structures; toluene has one methyl group (CH₃) while xylene has two. Due to their structural similarity and nonpolar nature, they are miscible.

Water and ethanol are also miscible. Ethanol (C₂H₅OH) can form hydrogen bonds with water molecules due to the presence of an -OH group, making these substances compatible and able to form a homogenous mixture.

On the other hand, water is a polar solvent, and xylene is nonpolar, making them immiscible. Polar substances like water do not mix well with nonpolar substances like xylene because the attractive forces between water molecules (hydrogen bonding) are stronger than the interactions with nonpolar molecules.

Answer 2

Toluene and xylene, both nonpolar solvents, are miscible, as are water and ethanol due to their polar nature and hydrogen bonding capability. In contrast, water and xylene are immiscible because of the significant difference in polarities between the polar water and nonpolar xylene. Option ii

Step-by-step explanation:

The miscibility of liquids depends on the similarity of their polarities. Miscible liquids can dissolve in each other in all proportions, while immiscible liquids do not mix to a significant extent. The given liquid pairs in the student's question exhibit different miscibility:

I. Toluene (C7H8) and xylene (C8H10): Both toluene and xylene are nonpolar hydrocarbon solvents. Since they share similar nonpolar characters, they are miscible.

II. Water and ethanol (C2H5OH): Ethanol is polar and can form hydrogen bonds, making it miscible with water, another polar substance with strong hydrogen bonding.

III. Water and xylene (C8H10): Water is a polar molecule, while xylene is nonpolar, so they are not miscible; they form separate layers when mixed together.

From the options provided, toluene (C7H8) and xylene, both being nonpolar, would dissolve in each other, making option I correct. Similarly, water and ethanol (C2H5OH) are also miscible due to their polar nature and ability to form hydrogen bonds, making option II correct.

However, water and xylene are immiscible, which makes option III wrong. Miscible pairs from the other given examples would be cyclohexane and ethanol, both capable of hydrogen bonding, and methanol and acetone, which are both polar and can mix together well. Option ii