Explanation:
(a) [tex]Na_2S+HCl\rightarrow H_2S+2NaCl[/tex]
This is acid base reaction because there is no change of oxidation state on either side of the reaction.
(b) [tex]2Na+2HCl\rightarrow H_2+2NaCl[/tex]
This is a oxidation reduction reaction because sodium in elemental state ( 0 oxidation state) oxidizes to Na⁺ in NaCl. Also H⁺ in HCl reduces to H° in H₂.
(c) [tex]Mg+Cl_2\rightarrow MgCl_2[/tex]
This is a oxidation reduction reaction because magnesium in elemental state ( 0 oxidation state) oxidizes to Mg²⁺ in MgCl₂. Also Cl° in Cl₂ reduces to Cl⁻ in MgCl₂.
(d) [tex]MgO+2HCl\rightarrow H_2O+MgCl_2[/tex]
This is acid base reaction because there is no change of oxidation state on either side of the reaction.
(e) [tex]K_3P+2O_2\rightarrow K_3PO_4[/tex]
This is a oxidation reduction reaction because phosphorous in P³⁻ in K₃P oxidizes to P⁵⁺ in K₃PO₄ and oxygen reduces.
(f) [tex]3KOH+H_3PO_4\rightarrow K_3PO_4 + 3H_2O[/tex]
This is acid base reaction because there is no change of oxidation state on either side of the reaction.
