1)Ba(ClO3)2(s)--->BaCl2(s)+3O2(g) - Redox reaction
2)2NaCl(aq)+K2S(aq)--->Na2S(aq)+2KCl(aq) - None of the above
3)CaO(s)+CO2(g)--->CaCO3(s) - None of the above
4)KOH(aq)+AgCl(aq)---->KCl(aq)+AgOH(s) -precipitation reaction
5)Ba(OH)2(aq)+2HNO2(aq)--->Ba(NO2)2(aq)+2H2O(l) - Acid-base neutralization reaction
In this reaction, chlorine is reduced and oxygen is oxidized. Both reduction and oxidation occur in this reaction. Therefore, this is a redox reaction.
In this reaction, both Na2S and KCl are soluble in water. Therefore the reaction is non of the above. Since it can not be a double displacement reaction in which two compounds react and cations and anions exchange their places to form new compounds.
In this reaction CaO and CO2 combine to form calcium carbonate. This is a synthesis reaction, and thus its none of the above choices
In this reaction, the salt KCl is soluble in water and AgOH is insolubel in water. Therefore, this is a precipitation reaction.
In this reaction, nitrous acid acts as an acid and barium hydroxide acts as a base. Therefore, barium hydroxide and nitrous acid react to form salt and water. Therefore, this reaction is acid-base neutralization reaction.