Question

karrys teacher gave her two compounds for her to compare and analyze for identification.

• substance a was a colorless solid.
• substance b was a colorless liquid.

when karry heated both of the compounds, substance b had a boiling point that was significantly lower than the melting point of substance a.
based on the information provided, which of the following statements are true?

a there is not enough information provided to make conclusions about substance a and substance b.

b substance a is most likely an ionic compound because it has a higher melting point than the boiling point of substance b.

c since it is liquid at room temperature, substance b is most likely an ionic compound.

d it would take more energy to break the bonds in substance b, in order to overcome the strong electrostatic forces holding the bonds together.

Explanation:

• Option A: We can make conclusions based on properties of ionic and covalent compounds. Ionic compounds typically have high melting/boiling points, covalent (molecular) have low. So A is false.
• Option B: Ionic compounds have strong electrostatic forces, leading to high melting/boiling points. Substance A is solid (so has a melting point) and Substance B (liquid) has a boiling point much lower than A's melting point. This fits ionic (A) vs covalent (B) properties. So B is true.
• Option C: Ionic compounds are usually solid at room temp (due to high melting points). Substance B is liquid, so it's unlikely ionic. C is false.
• Option D: Substance B likely has weak intermolecular forces (covalent), so less energy needed to break bonds. D is false.

Answer:

B. Substance A is most likely an ionic compound because it has a higher melting point than the boiling point of Substance B.