Correct answer is option (a) i.e. Calcium.
Calcium reacts with oxygen to give calcium oxide. Calcium oxide is soluble in water to give Calcium Hydroxide.
Carbon forms carbon-oxide with oxygen which is gas, hence option B is wrong Silicon reacts with oxygen and forms silicon dioxide. This is insoluble in water. So option C is not correct.
Iron reacts with oxygen and forms Iron dioxide. This is insoluble in water. So option D is not correct.
Answered by Vishal kumar | 1 year 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?