Oxalic Acid Lab Report

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Oxalic acid (H2C2O4.):

Oxalic acid is a colourless, toxic organic compound that is found naturally in plants, animals and in human beings. 16
It is also known as Ethanedioic acid or wood bleach. Oxalic acid is used to remove rust and stains in laundry as it converts most insoluble Fe compounds into soluble complex ions. It is also a constituent used to remove scale from automobile radiators.16
Oxalic acid has a molecular mass of 90.0349 g.mol-1. It is a strong acid and is in the carboxylic group. Although it is in the carboxylic group it is not as weak as the other carboxylic acids. Oxalic acid has 2 levels of ionisation as it is a diprotic acid. A diprotic acid is an acid that can donate 2 protons (H+ ions) per molecule to an aqueous solution. The ionisation reactions for oxalic acid are:
H_2 C_2 O_(4 (aq) ) ↔HC_2 O_(4 (aq))^(-1)+H_((aq))^+
HC_2 O_(4 (aq))^(-1) ↔ C_2 O_(4 (aq))^(-2)+ H_((aq))^+
The 1st ionization constant is 5,8 x 10-2 and the 2nd ionization constant is 6,5 x 10-5. Oxalic acid is both a Bronsted-Lowry and an Arrhenius acid. 10

It mainly exists as H2C2O4.2H2O, which is known as oxalic acid dihydrate. The 2H2O attached to the oxalic acid means that for every one molecule of Oxalic acid there is, there will be 2 molecules of water. This makes it predictable and allows for the standardization of NaOH. The reaction between NaOH and Oxalic acid dihydrate is as follows:

H2C2O4 .2H2O + 2NaOH → Na2C2O4 + 4H2O

This is a neutralization

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