(20 10. Taizhou, Zhejiang) 29. Coagulant should be added when tofu is processed. What is the chemical composition of coagulant? According to the data, coagulant may contain

(l)Ca(OH)z (or calcium hydroxide)? (2)Ba(N03)2+Na 2s 04 = bas 04↓+2 nan 03？ (3) Silver chloride

Analysis: according to the nature of substances and the phenomenon of chemical reactions, provide information analysis and answers in combination with topics;

Calcium hydroxide solution is alkaline, which can make phenolphthalein test solution turn red; Barium sulfate and silver chloride are insoluble in dilute nitric acid.

(? l？ )? Calcium hydroxide solution is alkaline, which can make phenolphthalein test solution turn red; Take a small amount of coagulant solution in the test tube, add a few drops of colorless phenolphthalein solution, and the test solution will not change color, indicating that it does not contain calcium hydroxide;

So the answer is: Ca(OH) 2 (or calcium hydroxide);

(2) Put a small amount of coagulant solution into a test tube, and add a proper amount of Ba(NO3)2 and dilute HNO 3 to show that barium sulfate precipitate is insoluble in water and generates dilute nitric acid, indicating that the coagulant contains sodium sulfate; Sodium sulfate reacts with barium nitrate to generate barium sulfate precipitate and sodium nitrate;

So the answer is: ba (n03) 2+na2so4 = bas04 ↓+2? nan 0 3；

(3) Take a proper amount of filtrate from Experiment 2 in a test tube, add a small amount of AgNO 3 solution and diluted HNO 3, and white precipitate appears, indicating that silver chloride precipitate is generated, indicating that the filtrate contains chloride ions;

So the answer is: AgCl ..