Why KHP is used in titration?

Why KHP is used in titration?

KHP is slightly acidic, and it is often used as a primary standard for acid–base titrations because it is solid and air-stable, making it easy to weigh accurately. It is not hygroscopic.

What is KHP in titration?

In. order to determine the exact concentration of a sodium hydroxide solution you must standardize it by. titrating with a solid acid that is not hygroscopic. Potassium hydrogen phthalate, KHC8H4O4 (abbreviated. KHP), is a non-hygroscopic, crystalline, solid that behaves as a monoprotic acid.

Which indicator is used in the titration of KHP And anyway?

To standardize a sodium hydroxide (NaOH) solution against a primary standard acid [Potassium Hydrogen Phthalate (KHP)] using phenolphthalein as an indicator.

Is potassium hydrogen phthalate an indicator?

When KHP is used as a basimetric standard (e.g., in standardization of Perchloric Acid in Glacial Acetic Acid), Methyl Violet or Crystal Violet indicator is commonly used….Potassium Hydrogen Phthalate.

Potassium Hydrogen Phthalate Potassium Acid Phthalate, KHP
Chemical Formula HOCO(C6H4)COOK
CAS No. 877-24-7

What is potassium hydrogen phthalate and why is it used for standardization of an NaOH solution?

Potassium hydrogen phthalate makes for a good primary standard because it is stable, high in purity, non-hydroscopic, highly soluble, non-toxic, high in molecular weight, cheap, and available. Needless to say in this quantitative experiment extra care was given in taking and recording measurements.

What is the purpose of titrating the pure KHP with the NaOH solution in Part A?

In the first standardization the molarity of a sodium hydroxide solution (NaOH) will be determined by titrating a sample of potassium acid phthalate (KHP; HKC8H4O4) with the NaOH. In the second procedure the standardized NaOH will be used to determine the molarity of a hydrochloric solution (HCl).

What color will the solution of potassium phthalate and phenolphthalein appear?

Since all the reactants and products of this neutralization reaction are colorless, a few drops of an indicator (phenolphthalein) were added to each KHP sample to be titrated. Phenolphthalein is colorless in acidic solution, but turns red in basic solution.

Why is phenolphthalein a good indicator for KHP and NaOH?

In the titration of acetic acid with aqueous NaOH, phenolphthalein is used as the indicator. Phenolphthalein is nearly colorless in acidic solution, but turns pink at a pH of about 8. This indicates that the base has neutralized all the acid.

What is the purpose of titrating the pure KHP with the NaOH solution in Part a?

How is KHP used to standardize NaOH?

When one drop more NaOH is added than is required to react with the KHP in a sample, the sample becomes basic and the indicator changes color. We take the point where the indicator color first appears as an indication that we have added NaOH in an equivalent amount to the KHP present in the sample.

How do you standardize NaOH with KHP calculations?

To Standardize: Record the amount of KHP and water used. Add 4 drops of indicator into the flask and titrate to the first permanent appearance of pink. Near the endpoint, add the NaOH dropwise to determine the total volume most accurately.

How will you know when to stop titrating the KHP solution with the NaOH solution in the Buret?

Keep the mass of KHP used as constant as possible. Calculate the concentration of your NaOH solution and the average deviation (as in lab 1). If the average deviation is less than 0.0002 M, you can stop.

Why is it important to keep the NaOH solution stoppered at all times when it is not in use?

Do not allow the rubber stopper to come in contact with the NaOH solution. Be sure to keep the solution stoppered when you are not using it (H2O reacts with CO2 in the atmosphere forming H2CO3).

Why does the indicator change color in titration?

The color change of a pH indicator is caused by the dissociation of the H+ ion from the indicator itself.

Why is phenolphthalein a good indicator for titration KHP with NaOH?

Phenolphthalein is colorless in acidic solution, but turns red in basic solution. When one drop more NaOH is added than is required to react with the KHP in a sample, the sample becomes basic and the indicator changes color.

Why do you standardize NaOH before titration?

But when it comes to anything analytical where you start to involve calculations, standardization is a must. This is done with NaOH because it’s hygroscopic and readily sucks up the moisture in the air. So what is being weighed isn’t totally NaOH, but also the moisture that it has absorbed.