1. (KHCJIOTbI) Fe+H_(2)SO_(4)(p-p)arrow CuO+HClarrow NaOH+H_(2)Sarrow BaCl_(2)+H_(2)SO_(4)arrow

1. $Fe+H_{2}SO_{4}(p-p)\rightarrow FeSO_{4}+H_{2}\uparrow$<br />2. $CuO+HCl\rightarrow CuCl_{2}+H_{2}O$<br />3. $NaOH+H_{2}S\rightarrow NaHS+H_{2}O$<br />4. $BaCl_{2}+H_{2}SO_{4}\rightarrow BaSO_{4}\downarrow+2HCl$