Question

which of these describes the formation of a mixture?
a sodium and chlorine reacting to produce table salt
b rust forming on an iron nail
c sugar crystals dissolving in water
d hydrogen and oxygen forming water

Explanation:

A mixture is formed when substances are combined without a chemical reaction (no new substance is formed).

• Option a: Sodium and chlorine react chemically to form table salt (a compound), so it's a chemical reaction, not a mixture.
• Option b: Rusting is a chemical reaction (iron + oxygen + water → rust, a new compound), so not a mixture.
• Option c: Sugar dissolving in water is a physical process where sugar (solute) and water (solvent) mix to form a solution (a type of mixture) with no new substance formed.
• Option d: Hydrogen and oxygen react chemically to form water (a compound), so it's a chemical reaction, not a mixture.

Answer:

c. sugar crystals dissolving in water