Phenolphthalein is added dropwise in sodium hydroxide solution. Add hydrochloric acid dropwise, the phenomenon is.

When phenolphthalein is added dropwise in sodium hydroxide solution, phenolphthalein turns red
Add hydrochloric acid again and the red will disappear

What happens when you drop phenolphthalein in sodium hydroxide solution?

It will turn red. If hydrochloric acid is added dropwise, it will be red if the amount is not enough. If the amount is just neutralized with sodium hydroxide, it will be colorless. If it is excessive, it will become acidic and colorless.

RELATED INFORMATIONS

1. Among the following reagents, salt solution, sodium hydroxide solution and dilute sulfuric acid can be identified as () A dilute hydrochloric acid B colorless phenolphthalein C litmus test solution D limestone Why?
2. 1 Color change range of common indicators: methyl orange () phenolphthalein () litmus ()
3. Determination of Color-Changing Range of Chemical Indicator Methyl Orange Phenol Phthalate Purple litmus Study on that color change range of methyl orange phenolphthalein purple litmus
4. Color change of phenolphthalein with acid and alkali Color change of purple litmus test solution with acid and alkali
5. Reaction of Copper with Concentrated Sulfuric Acid Copper is heated with concentrated sulfuric acid and 4.9g sulfuric acid is reduced in the reaction. (1) Volume of gas generated under standard condition (2) The solution after the reaction was prepared into a solution of 500 ml, and the amount and concentration of the substance in the solution were obtained Reaction of copper with concentrated sulfuric acid Copper is heated with concentrated sulfuric acid and 4.9g sulfuric acid is reduced in the reaction. (1) Volume of gas generated in standard condition (2) The solution after the reaction was prepared into a solution of 500 ml, and the amount and concentration of the substance in the solution were obtained Reaction of copper with concentrated sulfuric acid Copper is heated with concentrated sulfuric acid and 4.9g sulfuric acid is reduced in the reaction. (1) Volume of gas generated under standard condition (2) The solution after the reaction was prepared into a solution of 500 ml, and the amount and concentration of the substance in the solution were obtained
6. Dilute nitric acid and copper shall be heated. Dilute nitric acid and copper shall be heated
7. Does the reaction of copper with nitric acid require heating
8. What's the gas that makes the moist red litmus blue?
9. Is ammonia tested with wet purple litmus paper or wet red litmus paper? Can you use wet PH test paper?
10. What does the red litmus turn blue and the blue litmus turn red, respectively
11. What about dilute hydrochloric acid and dilute sulfuric acid with purple litmus solution and colorless phenolphthalein solution, respectively Answer separately above
12. Application method and phenomenon of acid - base indicator, such as colorless phenolphthalein test solution, purple litmus test solution, etc. Application method and phenomenon of acid - base indicator. such as colorless phenolphthalein test solution, purple litmus test solution, etc.
13. Excuse me why litmus test solution can not be used as indicator in acid-base neutralization titration, but phenolphthalein can I know because its color range is too large, not accurate, but its color range is pH 5.0-8.0, and phenolphthalein is 8.10.0, in the alkali solution is more accurate than litmus ah, why can not be used?
14. The following substances can not distinguish dilute hydrochloric acid from sodium hydroxide solution: A purple litmus B colorless phenolphthalein C sodium chloride solution D zinc particles
15. 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?
16. 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
17. 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
18. What can react with both HCl and NaOH?
19. 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.
20. 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