Barium is an element that is primarily used in fireworks because of its distinct green colour while on the other hand, lead is used in electrical industries due to its unique properties. The ions of these elements can simply be identified when its insoluble salts get precipitated by any process.
CaCI2 is for calcium chloride
Answer and Explanation:
The Fremy salt is a chemical compound its chemical name is disodium nitrosodisuphonate
The molecular formula of the Fremy salt is 
When phenol is treated with Fremy salt in presence of water then benzoquinone is formed
( in presence of Fremy salt and water)
The answer is c it is Carbon Dioxide
There is 103 percent of water in hydrate