Question

1. you would expect magnesium oxide to have a

□ low melting point and conduct electricity when solid
□ high melting point and conduct electricity when solid
□ low melting point and conduct electricity when dissolved
□ high melting point and conduct electricity when dissolved

Explanation:

Magnesium oxide (\(MgO\)) is an ionic compound. Ionic compounds have strong ionic bonds, resulting in a high melting point. In the solid state, ions are held in a fixed lattice and can't move freely, so they don't conduct electricity. When dissolved in water (or molten), the ions dissociate and can move, allowing electrical conduction. So we analyze each option:

• First option: Ionic compounds have high (not low) melting points, and don't conduct in solid. Eliminate.
• Second option: Don't conduct in solid. Eliminate.
• Third option: High (not low) melting point. Eliminate.
• Fourth option: High melting point (due to ionic bonds) and conducts when dissolved (ions free to move). Correct.

Answer:

D. high melting point and conduct electricity when dissolved (assuming the options are labeled A, B, C, D in order as presented, with the last option being D)