A H2CO3 (aq) ---> CO2 (g) + H2O (l) B H2SO4 (aq) + 2NaOH (aq) ---> Na2SO4 (aq) + 2H2O (l) C 2H2 (g) + O2 (g)> 2H2O (l) D AgNO3 (aq) + NaOH (aq) ---> AgOH (s) + NaNO3 (aq) Which equation above represents a precipitation reaction?

Explanation:

A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.  

A double displacement reaction in which one of the product is formed as a solid is called as precipitation reaction.  

The equation which represents a precipiation reaction is:

let that person have a turn to speak : )