Can we use phenolphthalein indicator for EDTA titration?

Can we use phenolphthalein indicator for EDTA titration?

No. Phenolphthalein cannot be used as an indicator for EDTA or complexometric titration.

Why phenolphthalein is not used in EDTA titration?

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. In fact it is usual to buffer the mixture to keep the pH approximately constant (at about pH 10 for Eriochrome Black T indicator).

Which indicator is used in CA EDTA titration?

The method uses a very large molecule called EDTA which forms a complex with calcium ions. EDTA stands for ethylenediaminetetraacetic acid. A blue dye called Patton and Reeder’s indicator (PR) is used as the indicator.

Why does phenolphthalein and methyl orange not used in EDTA titration?

The titration shows the end point lies between pH 8 and 10. Hence phenolphthalein is a suitable indicator as its pH range is 8-9.8. However, methyl orange is not suitable as its pH range is 3.1 to 4.5.

Why phenolphthalein is used as the indicator in this titration?

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. It is known as the titrant.

Why do we use phenolphthalein first then methyl orange?

When we use something like phenolphthalein as the end-point indicator, the color change corresponds to the first reaction. Methyl orange, on the other hand, is the perfect indicator for this scenario as it will change color corresponding to the completion of the overall reaction.

How does EDTA bind to calcium?

Disodium EDTA is a chelating agent used in studies involving calcium. The sodium ion of the chelate is displaced by calcium to form soluble, non-toxic physiologically unavailable complexes that are excreted through urine.

What can you use phenolphthalein for?

Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions.

What happens when phenolphthalein is added to HCL?

Colour of the hydrochloric acid solution does not change on addition of phenolphthalein indicator. Phenolphthalein indicator remains colourless in the acidic solution while its colour changes to pink in basic solution.

What happens if you add too much phenolphthalein?

The intensity of the color is concentration dependent, so if a large amount of phenolphthalein is present the color could be very strong at the end-point. However, the presence of a large amount of phenolphthalein is not usually the reason a titration mixture has an intense color.

Which is more stable CA-EDTA or EDTA?

The Ca-EDTA complex is more stable than the Mg-EDTA complex. Is EDTA a strong or weak acid? I agree with Douglas, it is not a strong acid.

How many times does EDTA bind to nitrogens?

EDTA is a hexadentate ligand, which means that it binds six times. It binds twice at the nitrogens and four at the oxygens. EDTA is used most commonly as salts and in a dry form. EDTA is a great chelating agent, allowing multiple bindings in a coordination complex.

What is the end point of EDTA titration?

In a titration to establish the concentration of a metal ion, the EDTA that is added combines quantitatively with the cation to form the complex. The end point occurs when essentially all of the cation has reacted. In this experiment you will standardize a solution of EDTA by titration against a standard solution made from calcium carbonate, CaCO3.

Is the first pKa of EDTA a strong acid?

For EDTA, the first pKa is about 2, which for an organic acid is modestly high. Having four acids, it has a total of 4 pKas, each indicating a weaker acid. pKa1, as noted, =2, pKa2=2.7, pKa3=6.2 and pKa4=10.31.