Experiment: A piece of sodium was dropped in water in a trough.Observation: It moved rapidly, producing fizzing and a colorless gas that burned with a pop.Question: What gas was released?
Correct answer: C. Hydrogen gas from sodium-water reaction.
- A. Carbon dioxide from water.
- B. Oxygen from salt decomposition.
- C. Hydrogen gas from sodium-water reaction.
- D. Nitrogen from sodium nitrate.
Explanation
The correct answer is Option C: Hydrogen gas from sodium-water reaction. When sodium is dropped in water, it reacts vigorously to produce hydrogen gas. The fizzing and the pop sound are characteristic of the hydrogen gas being released. Options A, B, and D are incorrect because sodium does not produce carbon dioxide, oxygen, or nitrogen when reacted with water.
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About Scientific Reasoning
Scientific reasoning evaluates hypotheses through observations, variables, controls, measurements and experimental results. Questions involve identifying independent and dependent variables, recognising a fair test, interpreting tables or graphs, distinguishing evidence from opinion, and deciding whether data supports, rejects or leaves a hypothesis unresolved.
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