When dilute hydrochloric acid is added to iron filings, hydrogen gas and iron chloride are produced.
Explanation: This reaction is a single displacement reaction where the iron displaces hydrogen from the hydrochloric acid, forming iron(II) chloride (FeCl2) and hydrogen gas (H2).
Why other options are incorrect:
b Chlorine gas and iron hydroxide are produced: This reaction doesn’t produce chlorine gas. Chlorine is a highly reactive halogen and its formation in this scenario would be highly unlikely. Iron hydroxide is also not the typical product. It’s more likely to form under different conditions, such as when iron reacts with a strong base.
c No reaction takes place: This is incorrect. Iron and dilute hydrochloric acid readily react.
d Iron salt and water are produced: While an iron salt (FeCl2) is produced, water is not the other product. The other product is hydrogen gas, not water.