Answer: Reaction of zinc with dilute sulfuric acid.
- A Reaction of zinc with dilute sulfuric acid
- B Simple electrolysis of pure water without any added electrolyte
- C Direct heating of water to its boiling point
- D Mixing solid NaOH pellets with cold water
Correct answer: A. Reaction of zinc with dilute sulfuric acid
Explanation: Zn + H<sub>2</sub>SO<sub>4</sub> (dil) → ZnSO<sub>4</sub> + H<sub>2</sub> is the common lab method to produce hydrogen gas.
Each water molecule's O-H bonds (covalent, solid) can hydrogen-bond (dashed) to neighbouring molecules, forming an extended network responsible for water's unusually high boiling point and density anomaly.
Concept context
The simplest and most abundant element in the universe. Study its unique position in the periodic table, isotopes (protium, deuterium, tritium), properties of water and hydrogen peroxide, and industrial uses.