Phenolphthalein Solution And Baking Soda Didnt Turn Pink

Why does phenolphthalein turn pink?

Phenolphthalein (HIn) is weakly acidic in nature. And in aqueous solution, it dissociates into [math]H^+[/math] and [math]In^-[/math] ions.The pink colour of the solution is due to the concentration of [math]In^-[/math] ions in the solution.Under acidic conditions, the concentration of [math]In^-[/math] in the solution is very low and concentration of [math]H^+[/math] is high, hence it is colourless.Similarly, under basic conditions, the concentration of [math]H^+[/math] ions is very low and concentration of [math]In^-[/math] is high, hence the solution is pink coloured.For example, Titration of HCl (0.1N) against NaOH (0.1N) in the presence of phenolphthalein indicator.10 ml Titrant ( HCl ) is taken in a conical flask and phenolphthalein (2–3 drops) is added to it.At this point, no Titrand (NaOH) is added to the solution.Therefore, Phenolphthalein is under acidic conditions and hence it is colourless.This solution is now titrated against Titrand ( NaOH).As soon as we add 10 ml of NaOH, complete Neutralisation takes place.HCl + NaOH ====> NaCl + [math]H_2[/math]O.At this point, Phenolphthalein indicator is under neutral conditions and it imparts very very light pink colour to the solution. This point is called as Equivalence point.Now, after the equivalence point we add 0.1 ml of NaOH.After this addition phenolphthalein comes under basic conditions and imparts Pink colour to the solution. This point is called as the End point.End point tells us that the reaction is completed.I hope, I’ve answered your query.Edit: Made answer more clear.

How do I write a chemical equation of phenolphthalein and sodium hydroxide?

Phenolphthalein is a indicator used for determining the quantity of base. The structure of phenolphthalein is as belowWhen phenolphthalein is reacted with acid or neutral solution or water there is no reaction as phenol present in the structure is acidic in nature i.e. it has tendency to release H+ ions in the solution. In presence of acid or neutral solution the H+ ion of phenol are not liberated. but when phenolphthalein is treated with a base. the acidic part of phenol reacts with the base to give corresponding  sodium salt of phenolphthalein which has pink color thus it imparts pink color to the solution  Thus in acid base titration phenolphthalein is used to detect end point of base.MyeTutors-Home

Why does the color of iodine solution turn blue when starch is added to it?

I hope this will help :What properties of starch (given its chemical structure) allow it to be used as an indicator? Davender Khera, Yale UniversityWhen starch is mixed with iodine in water, an intensely colored starch/iodine complex is formed. Many of the details of the reaction are still unknown. But it seems that the iodine (in the form of I5- ions) gets stuck in the coils of beta amylose molecules (beta amylose is a soluble starch). The starch forces the iodine atoms into a linear arrangement in the central groove of the amylose coil. There is some transfer of charge between the starch and the iodine. That changes the way electrons are confined, and so, changes spacing of the energy levels. The iodine/starch complex has energy level spacings that are just so for absorbing visible light- giving the complex its intense blue color.The complex is very useful for indicating redox titrations that involve iodine because the color change is very sharp. It can also be used as a general redox indicator: when there is excess oxidizing agent, the complex is blue; when there is excess reducing agent, the I5- breaks up into iodine and iodide and the color disappears.BTW...there is something known as GOOGLE. Next time you have such kind of doubts, please feel free to use it

What happens when a few drops of phenolphthalein are added to an acidic solution?

Hello there.We all know that phenolphthalein gives no colour when added to an acidic solution.Reason :-Phenolphthalein is an acid indicator,means when we add water (pH 7) to it,it ionises giving a pink colour. That pink colour is actually due to the phenolphthalein ion.Following is the ionisation reaction.[math]\displaystyle HIn + H_{2}O \rightleftharpoons H^{+} + In^{-}[/math][math]H^{+}[/math] is colourless and [math]In^{-}[/math](phenolphthalein ion) is pink coloured .So when we add phenolphthalein solution to acid or base,the colour depends on a condition,which is a basic of Ionic equilibrium chapter.If concentration of [math]H^{+}[/math] is greater than that of [math]In^{-} [/math]then the solution will be colourless.If concentration of [math]H^{+}[/math] is less than that of [math]In^{-}[/math] then the solution will be pink.We all know acid gives [math]H^{+}[/math] in solution. When we add phenolphthalein to acid due to common ion effect [math]H^{+}[/math] concentration increases. It becomes more than that of [math]In^{-}[/math] concentration. So it appears colourless.It is the reason of no colour when phenolphthalein is added in acid .But in case of base,the [math]OH^{-}[/math] ions combine with [math]H^{+}[/math] of the indicator and forms water. So [math]In^{-}[/math] concentration will be more. Solution will appear pink in basic medium.Here is a picture I found in internet.Hope that helps.[math]Tripathy.[/math]

What happens when you add hydrochloric acid to sodium carbonate?

Acid carbonate reactionProducts : carbon dioxide gas, water and salt sodium chlorideCarbon dioxide gas released as effervescence or bubbles, test for its presence using calcium hydroxide, slaked lime, by bubbling it into limewater to produce a chalky white precipitate of calcium carbonate.