alleryWhen an acid reacts with a metal, the gas usually evolved is:
AOxygen
BHydrogen
CChlorine
DCarbon dioxide
Answer & Solution
Correct answer: B. Hydrogen
1. Metal + dilute acid → salt + hydrogen.
2. E.g. Zn + 2 HCl → ZnCl₂ + H₂↑ (with the characteristic 'pop' test for H₂).
3. With nitric acid this isn't always seen (HNO₃ is also an oxidising acid).
_Source: syllabus Science Ch 2 §2.1.2 Acids with Metals_
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