All acids produce _________ gas on reacting with metals.

Correct option is B

The correct answer is (b) Hydrogen.
· When acids react with metals, they typically produce hydrogen gas. The general reaction can be represented as:
Acid+Metal→Salt+Hydrogen gas
Information Booster:
· Example: When hydrochloric acid (HCl) reacts with zinc (Zn), it produces zinc chloride (ZnCl₂) and hydrogen gas (H₂):
2HCl+Zn→ZnCl2+H2
· Hydrogen Test: The presence of hydrogen gas can be confirmed by bringing a burning matchstick near the gas; it will produce a 'pop' sound, which indicates hydrogen.
· Exceptions: Not all metals react with acids to produce hydrogen gas. For example, metals like gold and platinum do not react with acids in this way due to their low reactivity.