Why phenolphthalein is not a suitable indicator for the titration of Na2CO3 with HCl?

Na2CO3 act as a weak base and HCl is a strong acid. Phenolphthalein is not a suitable indicator for titrating weak base against strong acid because the equivalence point of the titration will result in an acid salt(NaHCO3) which cannot go to completion.

Does phenolphthalein react with Na2CO3?

Phenolphthalein changes its colour from colourless to pink from acidic to basic medium. But sodium carbonate is relatively more basic than sodium bicarbonate and turns the solution to pink when phenolphthalein is added.

Why does phenolphthalein solution Cannot be used as an indicator in titration of strong acid and weak base?

Hence the main reason is that phenolphthalein is a weaker acid than the acid that is to be titrated. The endpoint pH (equivalent point) of a reaction between a weak acid and a strong base is given by pH = 1/2 pKw + 1/2pKa + 1/2 log [acid]. Phenolphthalein changes color in the pH range of 8.3 to 10.

What is the colour of phenolphthalein in Na2CO3 solution?

when a few drops of phenolphthalein is added to an aqua solution of sodium carbonate then the colour will change to pink. Explanation: Sodium carbonate is formed by a strong base and a weak acid.

Why is phenolphthalein a suitable indicator for this reaction?

A strong acid- strong base titration is performed using a phenolphthalein indicator. Phenolphtalein is chosen because it changes color in a pH range between 8.3 – 10. It will appear pink in basic solutions and clear in acidic solutions. Neutralization is the basis of titration.

Why the indicator phenolphthalein Cannot be used for the determination of bicarbonate alkalinity?

As already pointed out by Kristina Kucanda, phenolphthalein changes colour to pink when the pH is above 8.2. Hence, it is not a suitable indicator for bicarbonates. Indicator choice is based on the pH of the equivalence point for the acid-base titration you are doing.

Why phenolphthalein Cannot show any colour even at pH 7?

Phenolphthalein is a weak acid and is colorless in solution although its ion is pink. Adding hydroxide ions (OH-, as found in bases) will change the phenolphthalein into its ion and turn the solution pink.

What happens when phenolphthalein is added to NaHCo3?

Phenolphthalein=Phenolphthalein is a compound mostly used as a ph indicator in acid-base titrations, when reacted with baking soda, phenolphthalein would change colour from colourless to pink because baking soda has a ph of 9. 2.

Why phenolphthalein is not used in complexometric titration?

Why is phenolphthalein not used as an indicator in EDTA titration? – Quora. Because phenolphthalein is an acid-base indicator (responds to pH) whereas EDTA titration is not an acid base one, but operates on a different principle.

Why can’t phenolphthalein be added to the titration mixture used in the determination of PKA?

In the same way in the Titration of weak base versus strong acid there is a sudden change in the pH of 3.5 to 8.0,near the neutralisation point. So Phenolphthalein can’t be used since its pH range is 8.3 to 10.0.

Why does phenolphthalein not indicate the neutralization for bicarbonate ion?

Let’s use phenolphthalein as the indicator and HCl for titrating the mixture. The pH at this point isn’t alkaline enough for phenolphthalein to become colourless. Phenolphthalein changes color between 8–10 and the pH of bicarbonate (formed after half-titration of carbonate) lies in this range.

Why phenolphthalein Cannot show any Colour even at pH 7?

How do you titrate phenolphthalein with NaOH and HCl?

Let’s use phenolphthalein as the indicator and HCl for titrating the mixture. The first reaction that takes place is $$\\ce{NaOH + HCl -> NaCl + H2O}$$ The pH at this point isn’t alkaline enough for phenolphthalein to become colourless, since there’s still base ($\\ce{Na2CO3}$) present in the solution.

What is the colour change of phenolphthalein?

Phenolphthalein is naturally colourless and works differently then litmus paper. Also, it turns in pink colour in an alkaline solution or base. Moreover, the compound remains colourless in acids but starts to turn pink on pH 8.2 and continues to turn bright purple in strong bases. Colour Change of Phenolphthalein

What is the pH of bicarbonate in phenolphthalein?

Phenolphthalein changes color between 8–10 and the pH of bicarbonate (formed after half-titration of carbonate) lies in this range. Suppose you want to find out the amount of sodium carbonate in a solution of sodium hydroxide. Let’s use phenolphthalein as the indicator and HCl for titrating the mixture.

What happens when Na2CO3 reacts with HCl?

When Na2CO3 reacts with HCl, the compound is neutralized in a step-wise manner, that is, NaHCO3 is formed first before they are completely transformed to H2CO3 (or CO2 + H2O). At the start of the titration, the addition of phph to the analyte solution will cause it to turn into pink.