(i) Iron reacts with steam to form a magnetic oxide of Fe with the liberation of H2.
3Fe(s) + 4H2O(g) → Fe3O4(s) + 4H2(g)
(ii) Calcium reacts with water to form calcium hydroxide and hydrogen.
Ca(s) + 2H2O(I) → Ca(OH)2(aq) + H2(g)
Potassium reacts with cold water violently immediately with evolution of H2 which catches fire.
2K(s) + 2H2O(I) → 2KOH(aq) + 2H2(g)Answered by Shivani Kumari | 2 years ago
A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?