Generally,metals are solid in nature. Which one of the following metals is found in liquid state at room temperature?

What is the chemical formula for potassium dichromate?

$(a)$ Show the formation of $MgO$ by the transfer of electrons.
$(b)$ Name the cation and anion.
$(c)$ Write three properties of ionic compounds.

By which method/process is sulphur obtained from the earth's crust?

Why do ionic compounds have high melting points? State the reason.

Iqbal treated a lustrous,divalent element $M$ with sodium hydroxide. He observed the formation of bubbles in the reaction mixture. He made the same observations when this element was treated with hydrochloric acid. Suggest how can he identify the produced gas. Write chemical equations for both the reactions.