Preparation of M/10 Sodium Carbonate Solution

Standard liquid solutions, like acids, are readily available and straightforward to prepare. One can create standard solids solutions by measuring a solid mass and dissolving it into a volumetric flask with a known volume of solution. Sodium carbonate (Na2CO3) is practically insoluble in almost saturated sodium hydroxide.

Following the saturation, NaOH has equilibrated for several days, the insoluble Na2CO3 might sink to the bottom of the vessel. The supernatant can be carefully removed to get a diluted NaOH solution clear of Na2CO3. Since dissolved CO2 can create a titration error, the water utilized to prepare the NaOH standard solution should indeed be heated to eliminate it. The preparation of Na2CO3 is explained below.

Table of Content

• Aim

• Procedure

• Result

Aim

To prepare the $\dfrac{M}{{10}}$ standard solution of sodium carbonate.

Apparatus Required

1. 250 mL beaker

2. 250 mL 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. Na2CO3 is a primary standard. Sodium carbonate molar mass is 106. To prepare the $\dfrac{M}{{10}}$standard solution of sodium carbonate,

Molarity=$\left( {\dfrac{W}{M}} \right) \times V$

W is the sodium carbonate mass in grams.

M is the sodium carbonate molar mass in grams.

V is the volume of the solution, litres.

Procedure

Preparation of Sodium Carbonate Solution

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 2.650 g of Na2CO3 on the watch glass and record the weight.

3. Using a funnel, delicately and cautiously transfer the Na2CO3 from the watch glass to a dry, clean 250mL beaker. To transfer 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 sodium carbonate dissolves, stir the solution in the beaker using a glass rod.  

5. Transfer the solution 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 and give it a little shake to evenly distribute the solution. Mark it as $\dfrac{M}{{10}}$ Na2CO3 solution.

Observations

Result

The result of the chemistry experiment on the preparation of $\dfrac{M}{{10}}$ sodium carbonate solution verified that: -

A 250 mL or $\dfrac{M}{{10}}$standard sodium carbonate 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 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.

2. 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.

3. 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, instead of splashing beyond the lip.

4. 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.

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 sodium carbonate?

Ans: Molarity=$\left( {\dfrac{W}{M}} \right) \times V$. 

3. How does sodium carbonate act?

Ans: Antacid.

4. What is sodium carbonate anhydrous?

Ans: Anhydrous sodium carbonate means Na2CO3 without water molecules.

5. Mention two uses of sodium carbonate.

Ans: Sodium carbonate is used in the manufacturing of soap, and as a pH modifier.

9. Calculate the amount of anhydrous Na2CO3 for the 250mL of $\dfrac{M}{{10}}$solution.

Ans: Mass of sodium carbonate in gram (W) = 250 

The molecular weight of sodium carbonate in grams (M) = 106

The volume of solution in litres $\left( V \right) = \dfrac{{250}}{{1000}} = 0.25$

Molarity =$\dfrac{1}{{10}}$

Hence, the amount of anhydrous Na2CO3 = $106 \times \left( {\dfrac{{0.25}}{{10}}} \right) = 2.65{\rm{ }}g$.

10. Mention the sodium carbonate experiment preparation process.

Ans: Sodium carbonate experiment can be prepared using electrolytic, dual process, etc. 

11. What is the general formula of hydrated sodium carbonate?

Ans:  Na2CO3.nH2O

12. What compounds have resulted from the dissolution of sodium carbonate in water?

Ans: Carbonic acid and sodium hydroxide (NaOH).

13.  Why can't a standard NaOH solution be made?

Ans:  NaOH cannot be weighed as it absorbs moisture, thus it prevents the direct preparation of its standard solution.

Practical-Based Questions

1. What is the common name of sodium carbonate?

1. Table salt

2. Washing soda

3. Lime soda

4. Pearl ash

Ans: The common name of sodium carbonate is washing soda.

2. Name the process used for the preparation of sodium carbonate.

1. Solvay

2. Haber

3. Contact

4. None of the three options

Ans: The Solvay process is used for the preparation of sodium carbonate.

3. What is the molecular mass of washing soda in this experiment?

1. 1.059 g

2. 2.650 g

3. 1.350 g

4. None of the three options

Ans: The molecular mass of washing soda in this experiment is 2.650 g.

4. What type of compound is sodium carbonate?

1. Strong base

2. Weak base

3. Strong acid

4. Weak acid

Ans: Sodium carbonate is a strong base.

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 option

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

6. What is the pH of Sodium carbonate?

1. 8

2. 9

3. 10

4. 11

Ans: The pH of sodium carbonate is 11.

7. Why is sodium carbonate recommended for handling carefully during the experiment?

1. Since it is highly unstable

2. Since it is costly

3. Since it is highly corrosive

4. None of the three options

Ans: Sodium carbonate is recommended to handle carefully during the experiment since it is highly corrosive. 

8. What kind of substance is NaOH?

1. Hydroscopic

2. Hygroscopic

3. Efflorescent

4. None of the above

Ans: NaOH is a hygroscopic substance.

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.  How does sodium carbonate act towards heat?

1. Stable

2. Unstable

3. Vigorous

4. None of the three options

Ans: Sodium carbonate is stable towards heat.

Conclusion

This chemistry experiment on the preparation of $\dfrac{M}{{10}}$ sodium carbonate solution infers that the sodium carbonate is also known as washing soda. Na2CO3 is the chemical formula for sodium carbonate. The concentration of the 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 sodium carbonate solution, a total of 50 ml of distilled water should not be utilized.