h2o → X → Cah2 → h2 → hcl → h20
помогите пожалуйста

1: 2H_{2} O+Ca=Ca(OH )_{2}+H_{2} 2:Ca+H _{2} =CaH _{2}3:CaH _{2}+2H_{2} O=Ca(OH )_{2}+2H _{2}4: H_{2} +Cl _{2} =2HCl5:4HCl+O _{2} =2H _{2}O+2Cl _{2}