Answer:
See below
Explanation:
Ammonium 
is not a molecular ion because it is just a poly-atomic ion. A molecular ion has a "negative or positive charge" as a whole but the positive charge on here is not on the whole. So, it is a poly-atomic ion and not molecular ion.
A solid is hard and the molecules are packed together, a liquid can move around freely because the molecules aren't as packed together :)
If the equation is complete the products would be manganese chloride and oxygen gas would be given off.
MnCl2 + O2
