If you designed your own experiment to prove the law of conservation of mass, what conditions would be required?

1) No. of atoms of all elements participating in the reaction are to be balanced.
2) Pressure Change should be noted (because, if ∆P≈0, it shows the reaction is in equilibrium).
3) The theoretical representation of the reaction should be balanced well.

Acovalent bond is formed between the two hydrogen bonds

Ithink is a because if say increased in electronegativity