Why is phenolphthalein a good indicator for aspirin?

Phenolphthalein is an indicator because it changes color when all the aspirin has been reacted. This is called the “end point” of the reaction. If one continues adding NaOH after the end point, the solution will turn dark red. You want to stop the titration when the solution is a pale pink color.

How do you test the purity of aspirin?

To put it simply there is a visible violet color reaction. Because violet is the color with the shortest wavelength (400-420 nm) it can easily be measured by a Visual Spectrophotometer. The intensity of the color is related to the purity and concentration of aspirin in a tablet.

Which Colour is produced in identification test of aspirin?

IR absorption spectrum : The absorption maxima in the spectrum of sample corresponds in position and relative size to similarly recorded spectrum of Aspirin WRS. B. Melting point of precipitate : 156 º to 161 º C C. Colour test. : The colour becomes blue.

What is titration of aspirin?

Aspirin is a weak acid that also undergoes slow hydrolysis; i.e., each aspirin molecule reacts with two hydroxide ions. To overcome this problem, a known excess amount of base is added to the sample solution and an HCl titration is carried out to determine the amount of unreacted base.

What is the color of phenolphthalein blood test?

Phenolphthalein is a presumptive test that reacts with the heme molecule present in blood. A positive reaction gives a pink color.

How to calculate the amount of phenolphthalein in aspirin?

To each of three clean, labeled Erlenmeyer flasks, add 50 mL distilled water and three drops of phenolphthalein indicator. Use your HCl burette to add approximately 35, 40 and 45 mL of acid to flasks #1, #2 and #3, respectively, recording exactlyhow much acid is added to each flask within 0.01 mL. Swirl gently to mix.

How to determine the color of an aspirin sample?

Titrate the first aspirin sample with NaOH to the first permanent cloudy pink colour. 7. The aspirin/NaOH acid-base reaction consumes one mole of hydroxide per mole of aspirin.

Why does the phenolphthalein swab turn pink when taken?

The color of the swab will naturally turn pink due to oxidization in the air in about 30 seconds, so if findings aren’t recorded immediately, a false positive might be inadvertently registered. Sometimes the swab used for collection may be treated with ethanol to enhance the sensitivity of the hemoglobin to the Phenolphthalein.