Dolomite is an ore of which metal?

Which of the following represents the correct order of reactivity of metals?

An element $A$ burns with a golden yellow flame in air. It reacts with another element $B$ (atomic number $17$) to give a product $C$. An aqueous solution of product $C$ on electrolysis gives a compound $D$ and liberates hydrogen. Identify $A$,$B$,$C$,and $D$. Also,write down the equations for the reactions involved.

The electrical conductivity and melting point of an alloy is:

Which salts are formed when sulfuric acid reacts with metals?

Give two examples each of metals that are good conductors and poor conductors of heat,respectively.