In chlor-alkali process, chlorine and hydrogen gases are formed as by-products along with sodium hydroxide.
2NaCl(aq) + 2H2O(l)→2NaOH(aq) + Cl2(g) + H2(g)
Chlorine gas produces bleaching power when it reacts with lime water (Ca(OH)2). Bleaching powder is used as a bleaching agent in chemical industries.
Ca(OH)2(s)+Cl2(g)→CaOCl2(s)+H2O(l)
Therefore, X is chlorine gas, and Y is bleaching powder.