Go through the following question and provide the answer:
A metal carbonate X on reacting with an acid gives a gas which when passed through a solution Y gives the carbonate back. On the other hand, a gas G that is obtained at anode during electrolysis of brine is passed on dry Y, it gives a compound Z, used for disinfecting drinking water. Identity X, Y, G and Z.
Answer variants:
Calcium bicarbonate
Calcium carbonate
Bleaching powder
Hydrogen gas
Chlorine gas
Calcium hydroxide
Calcium nitrate
'X':
'Y':
'G':
'Z':
'Y':
'G':
'Z':