![](data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 72 71" width="72"></svg>)
Must alkali make purple litmus test solution turn blue, colorless phenolphthalein test solution turn red Alkali can make purple litmus test solution blue, colorless phenolphthalein test solution red
This sentence is wrong, should say: not necessarily!
For example, when sodium hydroxide is dissolved in water, the solution can make the phenolphthalein test solution turn red, because sodium hydroxide is dissolved in water and can ionize OH- radical ions. When the alkali is insoluble in water, it can not change the color of phenolphthalein. For example, copper hydroxide can not change the color of phenolphthalein, because it is insoluble in water and can not ionize OH- radical ions, so it has no such property. Therefore, the soluble alkali can change the color of indicator.
What color do litmus and phenolphthalein show when they encounter acid and alkali? Also, what is the reason why acids and alkalis change color?
The litmus turns red with acid and the litmus turns blue with alkali. The phenolphthalein turns red with acid and the phenolphthalein turns red with alkali.
RELATED INFORMATIONS
- 1. What color do litmus and phenolphthalein come from when they encounter acid - base solutions.
- 2. Color after adding phenolphthalein and litmus test solution to acid and alkali salt Must have color Color after adding phenolphthalein and litmus test solution to acid and alkali salt Must have color.
- 3. Al reacts with NaOH, NaAlO2 reacts with HCl, and Al reacts with NaO. Write their chemical reaction equations
- 4. It is proved that the chemical reaction between CO2 and NaOH must have occurred. Why can it be proved by adding HCl?
- 5. During the following chemical changes: XHCl YNaOH The substance represented by Z, X may be () A. Cu B. AgNO3 C. Ba (OH)2 D. CuO
- 6. Demonstrate chemical reaction between CO2 and NAOH Conclusion of experimental phenomenon 1. Pass CO2 into NAOH solution without obvious phenomenon. The CACO3 generated in the second step of the reaction is 2. Take the solution obtained from the above experiment and prove that the chemical reaction occurs when white precipitation occurs. In the test tube, drop the calcium chloride solution 3. Drop HCL into the white precipitate. What is the deficiency of this experiment? Conclusion of experimental phenomenon 1. Pass CO2 to CACO3 in the second step of reaction formation without obvious phenomenon in NAOH solution, 2. Take the solution obtained from the above experiment to form white precipitate, indicating that there is carbonate new product in reaction 1. In a test tube, the formation of a calcium chloride solution drops in, proving that chemistry occurs 3. Drop HCL white precipitate into white precipitate to dissolve and react There are bubbles.
- 7. What can react with both HCl and NaOH?
- 8. H2SO4 is required to neutralize a certain amount of NaoH 1 Mol, if hydrochloric acid is used instead, the amount of Hcl in hydrochloric acid shall be used
- 9. If mg a% caustic soda solution and ng a% dilute sulfuric acid solution are mixed and the litmus test solution is still purple, the numerical relationship between m and n is correct () A.m=n B.m > n C.m < n D. Inability to judge
- 10. Why does the indicator use phenolphthalein solution instead of litmus solution in the experiment of neutralization reaction of sodium hydroxide solution and dilute hydrochloric acid? Why does the indicator use phenolphthalein solution instead of litmus solution in the neutralization reaction of sodium hydroxide solution and dilute hydrochloric acid?
- 11. The egg white drops into the purple litmus in blue and the colorless phenolphthalein solution in red. The PH of the egg white may be ( 1-3 Is A 4-6 is B 7 is C 8-11 is D
- 12. Colorless phenolphthalein, purple litmus acid and alkali neutral what color? Is there anything else that can test for acid-base properties? Colorless phenolphthalein, purple litmus acid and alkali neutral what color? Is there anything else that can test for acid and alkali?
- 13. Color change range of methyl orange, phenolphthalein and litmus
- 14. Which can be used as acid-base indicator? (Except litmus and phenolphthalein)
- 15. What happens when baking soda is mixed with white vinegar, is it a physical or chemical change
- 16. Is sodium carbonate or sodium bicarbonate (and hydrochloric acid) used in the laboratory for carbon dioxide production
- 17. Someone eats barium chloride by mistake and causes poisoning, if take sodium sulfate solution in time can detoxify, reason (write chemical equation) Also why not take sodium carbonate (ibid.) Some people mistakenly eat barium chloride and cause poisoning. If you take sodium sulfate solution in time, you can detoxify it. Also why not take sodium carbonate (ibid.)
- 18. How to prepare 0.2mol hydrochloric acid solution 1000ml
- 19. When preparing 1000ml 0.2mol /L hydrochloric acid solution, take 36.5%(1.19g/mol) of concentrated hydrochloric acid in milliliters When preparing 1000ml 0.2mol / L hydrochloric acid solution, take 36.5%(1.19 g/mol) of concentrated hydrochloric acid in milliliters
- 20. Acetic acid acetic acid increases the concentration of acetate ion Why does zinc react with hydrogen ions? The ionization of acetic acid increases the concentration of acetate ion Why does zinc react with hydrogen ions?