Question

An element reacts with oxygen to give a compound with high melting point, this compound is also soluble in water , the element is likely to be ?

Answer 1

When carbon reacts with oxygen it forms carbon dioxide. this carbon dioxide is a gas. gases do not possess melting point. so option B is not correct 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 Calcium reacts with oxygen and forms calcium oxide. This calcium oxide dissolves in water and forms calcium hydroxide. The melting point of calcium oxide is nearly 2,5000C. So the answer is A