(1)氧
(2)氧化
(3)Na +[:O:O: ] 2 -Na +
(4)NaH+H 2O = NaOH+H 2↑
根据题意可知:X为氢,Y为氧,Z为钠,A为NaH,B为Na 2O 2,C为H 2O 2,NaH+H 2O = NaOH+H 2↑