An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be

You are given a hammer,a battery,a bulb,wires,and a switch.
$(a)$ How could you use them to distinguish between samples of metals and non-metals?
$(b)$ Assess the usefulness of these tests in distinguishing between metals and non-metals.

$A$ 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?

Food cans are coated with tin and not with zinc because

Why is sodium kept immersed in kerosene oil?

Which of the following methods is suitable for preventing an iron frying pan from rusting?