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:

Which alloy is used to prepare surgical instruments?

Which of the following pairs will give displacement reactions?

Which furnace is used to extract iron metal from its ore?

Describe ionic compounds on the basis of the following properties:
$(i)$ Strong force of attraction between positive and negative ions:
$(ii)$ Solubility of compounds in water.
$(iii)$ Electrical conductivity.

What happens when:
$(i)$ $A$ piece of calcium is dropped in water.
$(ii)$ Sodium is kept exposed in air.
$(iii)$ Iron nail is dipped in copper sulphate solution.
$(iv)$ Potassium is dropped in cold water.
$(v)$ Carbon dioxide is compressed in water at high pressure.
Give chemical equations involved in all the above reactions and balance them.