Preparation of M/10 Oxalic Acid Solution

Standard liquid solutions, like acids, are readily available and simple to prepare. By measuring a solid mass and dissolving it into a volumetric flask with a known volume of solution, one can prepare a standard solution. In this experiment with an oxalic acid example, the preparation of the standard solution is explained in detail. Oxalic acid is a dicarboxylic acid. It is indeed a white crystalline substance that dissolves in water to produce a colourless solution.

Table of Content

• Aim

• Apparatus Required

• Theory

• Procedure

• Observations

• Result

Aim

To prepare the \[\dfrac{M}{{10}}\] standard solution of oxalic acid.

Apparatus Required

1. 250mL beaker

2. 250mL Volumetric flask

3. Glass rod

4. Funnel

5. Pipette

6. Watch glass

7. Wash bottle

8. Chemical balance 

9. Weight box

Theory

A standard solution is one whose concentrations are precisely known. C2H2O4 is a primary standard. Oxalic acid molecular mass is 126. To prepare the \[\dfrac{M}{{10}}\] standard solution of oxalic acid,

Molarity= \[W = M \times V\]

W is the oxalic acid mass in grams.

M is the oxalic acid molecular mass in grams.

V is the volume of the solution, litres.

12.6 g of oxalic acid must be dissolved per litre of water for the preparation of \[\dfrac{M}{{10}}\] oxalic acid solution. As a substitute, \[\dfrac{{12}}{6} = 3.15\,gm\] of oxalic acid should indeed be dissolved in water to obtain precisely 250 ml of solution.

Procedure

Preparation of Standard Solution of Oxalic Acid 

1. Wash the watch glass using distilled water and dry it. Weigh the dry watch glass and record the reading.

2. Make a precise weight measurement of 3.15 g of C2H2O4 on the watch glass and record the weight.

3. Using a funnel, delicately and cautiously transfer the C2H2O4 from the watch glass to a dry, clean 250mL beaker. For transferring the particles stuck to the watch glass into the funnel, rinse the watch glass using distilled water. Not more than 50mL of distilled water should be used for this purpose. 

4. Until the rigid oxalic acid dissolves, stir the solution in the beaker using a glass rod.  

5. Transfer the solution in the beaker to the volumetric flask using a glass rod and funnel.

6. Using a wash bottle, gently pour sufficient distilled water into the flask to fill it to just beneath the mark that has been carved on it.

7. When the lower layer of the meniscus almost reaches the line on the flask, add the final few millilitres of distilled water drop-wise using a pipette.

8. Put a stopper on the volumetric flask as well as give it a little shake to evenly distribute the solution. Mark it as \[\dfrac{M}{{10}}\] C2H2O4 solution.

Observations

Result

The result of the chemistry experiment on the preparation of \[\dfrac{M}{{10}}\] oxalic acid solution verified that:-

A 250 ml or \[\dfrac{M}{{10}}\] oxalic acid standard solution has been successfully prepared.

Precautions

• Handle chemicals and apparatus with caution.

• Every apparatus should be rinsed with distilled water and dried before starting the experiment.

• The solution preparation should be done while wearing an apron. 

• Avoid spilling the chemicals on the weighing balance during weighing.

• To make the solution uniform, it must be thoroughly shaken.

• When preparing the solution, the solvent must indeed be added so that its lower meniscus touches the flask's mark. 

• After the completion of the experiment, wash your hands thoroughly.

Lab Manual Questions

1. Why should the funnel and beaker be rinsed while preparing the solution?

Ans: Rinsing prevents any dissolved solute from being lost by ensuring that all particles enter the volumetric flask from the remaining solution in the funnel and the beaker.

2. What is the aim of transferring solutions employing glass rods?

Ans: Solutions are poured using glass rods to prevent spillage. A glass rod placed against a beaker's pouring edge enables the solution to run down the glass rod and into the collecting vessel, as opposed to splashing beyond the lip.

3. Why doesn't the pipette blow out the final drop?

Ans: Due to surface tension, a tiny drop of liquid remains in the pipette after the last drop is added, preventing the last drop from being blown out. Furthermore, the design of pipettes ensures that this drop won't have an impact on the empirical value.

4. Why is it necessary to close the volumetric flask once the solution is prepared?

Ans: The solute's ability to interact with the moisture of the oxygen or absorb carbon dioxide or some additional pollutant in the air is dependent on the solute.

Viva Questions

1. Define molarity.

Ans: The number of moles of a solute per litre of a solution is known as molarity. Another term for molarity is the molar concentration of a solution.

2. What is the formula to calculate the molarity of oxalic acid?

Ans: Molarity=\[W = M \times V\]. 

3. How does oxalic acid act?

Ans: Reducing agent.

4. What is the correct way of diluting an acid?

Ans: The correct way of diluting an acid is to add acid into the water with constant stirring.

5. Mention two uses of oxalic acid.

Ans: Oxalic acid is used to remove ink stains, and as acid rinses in laundries.

6. What is the purpose of using the oxalic acid standard solution?

Ans: Oxalic acid standard solution can be employed to estimate an alkali solution's undetermined concentration. 

7. What is the general formula of hydrated oxalic acid?

Ans:  C2H2O4.2H2O

8. What kind of water is used for the preparation of the standard solution?

Ans: Distilled water is used for the preparation of standard solutions.

9. Define normality.

Ans: Following the conventional definition, normality is defined as the quantity of solute (measured in grams or moles) prevalent per litre of a solution.

Practical Based Questions

1. What is the other name for oxalic acid?

1. Ethanedioic acid

2. Boric acid

3. Sulfonic acid

4. Lactic acid

Ans: The other name of oxalic acid is ethanedioic acid.

2. What is the conjugate base of oxalic acid?

1. Acetate

2. Oxalate

3. hydroxide

4. None of the three options

Ans: The conjugate base of oxalic acid is the oxalate ion.

3. What is the molecular mass of oxalic acid?

1. 116 

2.  126

3. 136 

4. None of the three options

Ans: The molecular mass of oxalic acid is 126.

4. What type of compound is oxalic acid?

1. Strong base

2. Weak base

3. Strong acid

4. Weak acid

Ans: Oxalic acid is a weak acid.

5. What type of instrument is used in this experiment to add the last drop to avoid the extra drops in the solution while transferring the solution to a volumetric flask?

1. Dropper

2. Wash bottle

3. Pipette

4. None of the above three options

Ans: Pipette is used to avoid extra drops during solution preparation

6. What measurement is used to represent the standard solution's strength?

1. Gram per litre

2. Milligram per litre

3. Moles per litre

4. None of the above three options

Ans: The standard solution strength is expressed using moles per litre.

7. How is the strength of a particular solution determined?

1. Law of mass action

2. Equivalent law

3. Henry’s law

4. None of the three options

Ans: Equivalent law is used to determine the strength of a particular solution. 

8. How does oxalic acid act for metal cations?

1. Reducing agent

2. Oxidizing agent

3. Chelating agent

4. None of the above

Ans: Oxalic acid acts as a chelating agent for metal cations.

9. How does distilled water act in chemical laboratories?

1. Indicator

2. Solvent 

3. Universal solvent

4. None of the three options

Ans: Distilled water acts as a universal solvent in chemical laboratories.

10.  What is the stability of the oxalic acid standard solution?

1. Stable

2. Unstable

3. Vigorous

4. None of the three options

Ans: Oxalic acid standard solution serves as a stable solution.

Conclusion

This Chemistry experiment on the preparation of \[\dfrac{M}{{10}}\] oxalic acid solution infers that oxalic acid is also known as ethanedioic acid. C2H2O4 is the chemical formula for oxalic acid. The concentration of the oxalic acid standard solution can be determined with high accuracy. It is prepared to utilize only pure chemicals, and standardization is used to determine the precise concentration. A primary standard is a chemical that is utilized to standardize an extremely pure solution. While making the oxalic acid solution, a total of 50 ml of distilled water should not be utilized.