Which gas can be released when sodium hydroxide reacts with zinc?
Answer and explanation
Correct answer: Hydrogen
Zinc is amphoteric, so it can react with a strong base such as sodium hydroxide. In aqueous solution, zinc forms a soluble zincate species while water is reduced and hydrogen gas is evolved; a simplified equation is Zn + 2NaOH + 2H2O → Na2[Zn(OH)4] + H2. Thus hydrogen is correct, not oxygen, carbon dioxide, or chlorine.
Frequently asked questions
What is the correct answer to this question?
Hydrogen
Why is this the correct answer?
Zinc is amphoteric, so it can react with a strong base such as sodium hydroxide. In aqueous solution, zinc forms a soluble zincate species while water is reduced and hydrogen gas is evolved; a simplified equation is Zn + 2NaOH + 2H2O → Na2[Zn(OH)4] + H2. Thus hydrogen is correct, not oxygen, carbon dioxide, or chlorine.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
