## What happens when aspirin reacts with NaOH?

This is an acid-base reaction in which the acetylsalicylic acid reacts with the base sodium hydroxide to produce the salt sodium acetylsalicylate and water (acid + base → salt + water).

## Why excess NaOH is added in the assay of aspirin?

The slow aspirin/NaOH hydrolysis reaction also consumes one mole of hydroxide per mole of aspirin, and so for a complete titration we will need to use a total of twice the amount of NaOH that you have already used, plus we will add some excess NaOH to ensure we really have reacted with all of the aspirin in the sample.

How many moles of NaOH reacts with aspirin?

one mole
The aspirin/NaOH acid-base reaction consumes one mole of hydroxide per mole of aspirin.

How do you calculate percent purity of aspirin from a titration?

1 mole of aspirin will react with 2 moles of NaOH So the number of moles of aspirin must be 0.016/2 = 0.008 moles Molecular mass of aspirin (C9H8O4) = 180, so mass of acetylsalicylic acid = 0.008 * 180 = 1.44 g So % purity of aspirin = (1.44/1.504) * 100 = 95.74% The other titration results was calculated the same way.

### Why is back titration used in aspirin?

Using titration it would be difficult to identify the end point because aspirin is a weak acid and reactions may proceed slowly. Using back titration the end-point is more easily recognised in this reaction, as it is a reaction between a strong base and a strong acid.

### What it is the purpose of treating the ASA sample initially with sodium hydroxide?

Hydrolyzing acetylsalicylic acid with sodium hydroxide to form salicylate dianion and acetate ion. What is the role of NaOH? a. To accelerate the rate at which salicylic acid and acetic anhydride react to form acetylsalicylic acid and acetic acid.

What is the principle of back titration?

A back titration is a titration method where the concentration of an analyte is determined by reacting it with a known amount of excess reagent. The remaining excess reagent is then titrated with another, second reagent.

How do you calculate purity of aspirin?

#### How titration can be used to confirm the degree of hydrolysis 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 percentage yield of aspirin?

The percent yield of the aspirin obtained from the experiment is 46.3% yield. The higher the yield percentage, the higher the purity of the aspirin will be. Therefore, according to the results, the aspirin obtained is relatively impure.

Why is back titration used for aspirin?

What is the titration of aspirin?

Practical 1 – Aspirin Titration Aspirin Titration – Determining the purity of aspirin In this experiment you will determine the percentage purity of aspirin in two different strengths of over the counter aspirin tablets by performing a titration with sodium hydroxide. The chemical name for aspirin is acetylsalicylic acid.

## What is the chemical equation for Asprin and sodium hydroxide?

Aspirin (acetyl salicylic acid C9H8O4, abbreviated HAS) reacts with sodium hydroxide according to the following equation: HAS(aq) + NaOH(aq) ( H2O(ℓ) + NaAS(aq)

## How to titrate NaOH with sulfuric acid?

Click n=CV button above NaOH in the input frame, enter volume and concentration of the titrant used. Click Use button. Read number of moles and mass of sulfuric acid in the titrated sample in the output frame. Click n=CV button in the output frame below sulfuric acid, enter volume of the pipetted sample, read sulfuric acid concentration.

Is the titration curve of sulfuric acid diprotic?

Second, as sulfuric acid is diprotic, we could expect titration curve with two plateaux and two end points. However, that’s not the case.