Which of the following demonstrates a chemical reaction of water?
A.
Water boils to produce steam at 100° C (252)
B.
Water Dissolves sugar
C.
Water produces gas with sodium metal
D.
Water and all separate when combined
The correct answer is:
C. Water produces gas with sodium metal
Explanation:
- A. Water boils to produce steam at 100°C (212°F): This is a physical change, not a chemical reaction. Boiling is a phase change where water turns from liquid to gas (steam) without altering its chemical composition.
- B. Water dissolves sugar: This is a physical change, not a chemical reaction. Dissolving sugar in water involves a physical process where sugar molecules become dispersed in water but do not change chemically.
- C. Water produces gas with sodium metal: This is a chemical reaction. When water reacts with sodium metal, it produces sodium hydroxide (NaOH) and hydrogen gas (H₂). The reaction is:2Na+2H2O→2NaOH+H22 \text{Na} + 2 \text{H}_2\text{O} \rightarrow 2 \text{NaOH} + \text{H}_22Na+2H2O→2NaOH+H2This reaction involves a change in chemical composition, making it a chemical reaction.
- D. Water and all separate when combined: This statement is unclear but suggests separation of components, which is not indicative of a chemical reaction.
Thus, the example that demonstrates a chemical reaction of water is when it produces gas with sodium metal.