(2) Zinc nitrate and ferric nitrate? Zinc nitrate, iron nitrate, silver nitrate

Analysis: according to the color characteristics of the solution, analyze the occurrence of the reaction in the flow chart and analyze the composition of the obtained solid or solution.

(1) solution b is a colorless solution. It can be judged that solution B does not contain ferrous ions, so ferrous nitrate in the original solution is completely replaced. According to the metal activity, metallic silver in silver nitrate is replaced before iron. Therefore, the silver nitrate and iron nitrate in the stock solution are completely replaced, and the solid obtained after the reaction must contain the replaced metallic iron and silver. If too much zinc is added, the solid contains zinc;

Therefore, choose Ag and Fe; Zn；

Solid a must contain iron and silver. When dilute sulfuric acid is added, iron reacts with dilute sulfuric acid to generate ferrous sulfate and hydrogen.

Therefore, the answer is: Fe+H2SO4 = FeSO4+H2 ↑;

(2) Solution B is light green, indicating that ferrous nitrate in the stock solution has not completely reacted, so the amount of zinc added is insufficient; According to the sequence of reaction between salt solution and metal, it can be judged that the added metal zinc and silver nitrate solution continue to react with ferrous nitrate after complete reaction. Because the solution contains ferrous nitrate, it is impossible to judge whether the silver nitrate solution is completely reacted. Then the solutes in the solution after the reaction may include zinc nitrate, ferrous nitrate or zinc nitrate, ferrous nitrate and silver nitrate.

So the answer is: Zn(NO 3) 2, Fe (NO 3) 2; Zinc nitrate, ferric nitrate, silver nitrate.