What happens when crystalline `Na_2CO_3` is heated ?

Na_2CO_3 is a salt of

Answer the following questions : What happens when ethylene gas is heated at high pressure and high temperature in the presence of suitable catalyst?

What happens, when a metallic object is heated?

Answer the following questions: What happens when aluminium ore is heated with caustic soda? Write the balanced chemical equation for the same.

Answer the following questions : What happens when ethanol is reacted with sodium ?

Answer the following questions : What happens when ethanol is heated at 170⁰C with excess of con. Sulphuric acid ?

What happens when a potential difference is applied across the ends of a conductor?

What happens when a diamagnetic substance is placed in a varying magnetic field?

What happens when a guitar string is plucked ?