Education Journalist | Study Abroad Lead
Standard Solution refers to that solution whose concentration has been determined accurately. They are prepared by using the purest chemicals available, and the exact concentration is determined by the process of standardization. The substance used for the standardization of a solution that is highly pure is called a primary standard. Sodium Carbonate standard solution can be used to standardize hydrochloric acid solutions for data analysis. It may also do back titration studies on insoluble basic compounds such as Milk of Magnesia tablets. Its concentration remains stable throughout months or even years, or at least during the titration phase.
| Table of Contents |
Key Terms: Sodium Carbonate, Distilled Water, Evaporation. Soda Ash, Washing Soda, Inorganic Compound, Standard Solution, Sodium Hydroxide
Aim
[Click Here for Sample Questions]
To prepare a 250 cm3 of N/10 standard solution of sodium carbonate.
Materials Required
[Click Here for Previous Year Questions]
- 250ml beaker
- 250ml measuring flask
- Chemical balance
- Distilled water
- Funnel stand
- Funnel
- Glass rod
- Sodium Carbonate
- Wash bottle
- Watch glass
- Weighing tube
- Weight box
| Topics Related to Solutions | ||
|---|---|---|
| Specific Conductivity of a Solution | Volumetric Analysis | Enthalpy of Dilution |
| Sodium Bicarbonate | Types of Solutions | Ferric Hydroxide Solution |
Theory
[Click Here for Sample Questions]
In very saturated sodium hydroxide, sodium carbonate is almost insoluble. Just after saturated NaOH has equilibrated for a few days, the insoluble sodium carbonate will fall to the bottom of the vessel. The precipitate can be properly removed to make a diluted NaOH solution devoid of Na2CO3. Because residual CO2 might create a titration mistake, the water used to prepare the NaOH standard solution must be heated. To make a standard solution of sodium carbonate, the equivalent weight of sodium carbonate is
= Equivalent weight / 2
= 106 / 2
= 53
A normal solution of sodium carbonate, having a volume of 1000cm3, generally requires 53g of sodium carbonate. Hence, 250cm3 of N/10 sodium carbonate will require
= (53 / 1000) x (250 / 10)
= 1.325 g.
Procedure
[Click Here for Previous Year Questions]
The procedure of the experiment is:
- Take out a watch glass. Wash it gently with the distilled water and dry the glass.
- Once the watch glass is cleaned and dried, carefully weigh the watch glass and write down the weight of the glass in your notebooks.
- Now carefully weigh the 1.325g of sodium carbonate. Place the salt on the watch glass and re-weigh the watch glass. Write down the new value of the weight of the watch glass in your copy.
- Use a funnel in order to transfer the sodium carbonate from the watch glass to a cleaned and dried measuring flask.
- Clean the watch glass with distilled water using a wash bottle to move the particles attached to it into the foam.
- The amount of distilled water used should not be more than 50 ml.
- Rinse the funnels with distilled water several times with a wash bottle to remove the clinging particulates into the measuring flask. Add water in small quantities when washing the funnel. The quantity of distilled water used should be no more than 50 mL.
- To transfer the solutions from the funnels to the measuring flask, properly clean the funnel with distilled water that used a wash bottle.
- Shake the measuring flask to dissolve the sodium carbonate.
- Using only a wash bottle, fill the measuring flask underneath the engraved mark with distilled water.
- Fill the measuring flask with the remaining few mL of distilled water until the lowered meniscus level reaches the marking.
- Place the cork over the flask's mouth and shake thoroughly to ensure that the required solution is uniform. Compute it as sodium carbonate (Na2CO3) N/10 solution.
Preparation of Standard Solution
Read More: Preparation of Standard Solution of Oxalic Acid
Observations
[Click Here for Sample Questions]
The observations of the experiment are:
| Weight of the watch glass | W1g |
|---|---|
| Weight of the watch glass + Sodium carbonate | W1 + 1.325 g |
| Weight of Sodium carbonate | 1.325 g |
| Volume of distilled water | 250 cm3 |
Results
[Click Here for Previous Year Questions]
250cm3 of decimolar or N/10 standard solution of sodium carbonate has been prepared.
Read More: Titration of Hydrochloric Acid against Standard Sodium Carbonate
Precautions
[Click Here for Sample Questions]
- The funnel is to be washed multiple times for the most accurate results during the experiment.
- An apron should be worn while preparing the solution.
- A pipette should be used to add the last drops in order to avoid any extra drops in the solution of the distilled water near the mark of the measuring cylinder, which is present on its neck.
- Try not to spill any substance on the balancing pan of the weight machine.
- The solvent should be added to the solution so that the bottom meniscus of the solvent is on the mark of the measuring flask.
- All the bases are highly corrosive; they should be handled carefully to avoid injuries.
- The watch glasses used in the experiment should be well cleaned and dried.
- The solution should be carefully shaken so that it becomes uniform.
Things to Remember
- Sodium carbonate is also called soda wash or washing soda.
- The formula of sodium carbonate is Na2CO3.
- The standard solution is a solution whose concentration may be calculated extremely precisely.
- It is prepared by using pure chemicals, and the exact concentration is determined by a process called standardization.
- The substance used for the standardization of a solution that is highly pure is called a primary standard.
- The total amount of distilled water used should not exceed 50 ml while preparing the solution of sodium carbonate.
- Because all bases are very corrosive, they must be handled with caution to avoid injury.
Previous Year Questions
- When 25 g of a non-volatile solute is dissolved in 100 g of water… [BITSAT 2008]
- The vapour pressure is due to… [KCET 2012]
- 0.15 g of a substance dissolved in 15 g of a solvent higher by 0.216∘C… [NEET 1999]
- 1 M and 2.5 litre NaOH solution mixed with another 0.5 M and 3 litre NaOH… [NEET 1980]
- 200 mL of an aqueous solution of a protein contains its 1.26 g… [NEET 2011]
- For an ideal solution, the correct option is… [NEET 2019]
- A 5% solution of cane sugar (MW = 342) isisotonic with 1% solution… [NEET 1998]
- An ideal solution is formed when its components… [NEET 1988]
- For determination of molar mass of colloids, polymers and protein… [NEET 2000]
- A solution of acetone in ethanol… [NEET 2006]
Sample Questions
Ques. What is sodium carbonate's chemical formula? What are the risks of sodium carbonate? (3 Marks)
Ans. Na2CO3 (sodium carbonate) is an inorganic compound. Washing soda, soda ash, and soda crystals are some other names. Sodium carbonate is potentially bad for health and safety. When this substance is breathed, it can induce discomfort in the respiratory system, cough, breathlessness, and pulmonary oedema.
Ques. What do you understand by the term anhydrous sodium carbonate and explain the uses of sodium carbonate? (3 Marks)
Ans. The formula for hydrated sodium carbonate is Na2CO3.nH2O, and it completely decomposes on high heat into water and anhydrous sodium carbonate, Na2CO3. Sodium carbonate is primarily used as a softener of water, food manufacturing aid, pH adjuster, a chemical used in a swimming pool, and electrolyte.
Ques. What do you mean when you say acidimetry? From where is sodium carbonate extracted? (3 Marks)
Ans. Acidimetry evaluates the strength of acid by titrating it with an appropriate indicator against a standard alkali solution. It is found and extracted in vast natural deposits in Wyoming and from lake brines in California (with other chemicals). Sodium carbonate is largely utilized in the production of glass and chemical processing.
Ques. How much sodium carbonate is needed to make 250 mL of 1 normality solution? (3 Marks)
Ans. Na2CO3 molecular mass = (23*2) + 12 + (16*3)
= 56 + 12 + 48
= 106
Equivalent weight = Molecular mass of Na2CO3 / Na2CO3 acidity
= 106 ÷ 2
= 53
Weight of solute dissolved per litre of fluid= normality * solute equivalent
Normality = 1 (assumed)
250 ml is the given volume
1/4 for mL = 250/1000
= (53) * (1/4)
= 13.25 g
Ques. Explain the reasons sodium carbonate is water-soluble? Why can't a standard NaOH solution be made? (3 Marks)
Ans. The reasons that sodium carbonate is water-soluble are as follows:
- Water's polarity allows it to dissolve many ionically bound compounds.
- Positive sodium ions are linked to negative chloride ions to form sodium carbonate.
- So, because a positive portion of water molecules attracts the negative carbonate ions and the negative part of water molecules attracts the positive sodium ions, water may dissolve sodium carbonate.
NaOH is a hygroscopic substance. It cannot be weighed because it absorbs moisture, and hence its standard solution cannot be produced directly.
Ques. State the differences between sodium carbonate and sodium bicarbonate. (4 Marks)
Ans. Sodium carbonate is often known as soda ash or washing soda. Sodium carbonate is a chemical compound composed of sodium and acid. In a number of applications, sodium carbonate is used to neutralise acidic liquids. Sodium carbonate is employed in physiological processes or reactions. When exposed to acid, it degrades into sodium bicarbonate. It is also an excellent electrical conductor. Sodium carbonate is a basic salt composed of a strong base (NaOH) and a weak acid (COOH) (H2CO3).
Sodium bicarbonate is another term for baking soda. Sodium bicarbonate is a chemical compound composed of sodium, acid, and hydrogen. Sodium bicarbonate is a weaker monoprotic base. Sodium bicarbonate is an essential nutrient in our systems. It helps to manage and neutralise high levels of blood acidity. Sodium bicarbonate is also used as an odour neutralizer, a temporary fire extinguisher and a cleaning or exfoliating agent.
Ques- How much Na2CO3 is needed to make 250 mL of 0.2 N sodium carbonate solution? (3 Marks)
Ans. For salt (Na2CO3), normality (N) = n factor X molarity (M)
where n factor is the number of moles of electron implicated by 1 mole of the salt.
Because there are two electrons involved here, the n factor for Na2CO3 is 2.
0.2 N Na2CO3 = 0.2/2 M Na2CO3
= 0.1 M Na2CO3
= 0.1 mole x Na2CO3 molecular mass
= 0.1 mole x 105.99 g/L
= 10.6 g/L
The quantity of Na2CO3 needed to make 250 mL of 0.2 N or 0.1 M Na2CO3 is
= 250 mL/1000 mL x 10.6 g Na2CO3
= 2.65 g.
Ques. How much 98 per cent pure Na2CO3 is needed to make 5 litres of 1N solution? (3 Marks)
Ans. Normality x Volume = Gram equivalent (in litre)
gramme equivalent needed is 1 x 5 = 5.
Equivalent mass = molar mass / n-factor
= 106 / 2
= 53
Gm equivalent = mass of compound / equivalent mass
mass of compound = 5 x 53
= 265 g
In 100g of sample, there is now 98g of Na2CO3.
Quantity required for 265g Na2CO3 is
= 100 x 265/98
= 270.408g.
Ques. What are the uses of sodium carbonate? (5 Marks)
Ans. Sodium carbonate can be used in the following ways:
- It is used to alter the pH.
- Carbonate precipitates hard water, including magnesium and calcium ions, and is used as a water softener.
- As both a laboratory and analytical reagent for acid standardization.
- It can be used in the brick industry as a wetting agent.
- It can be used in toothpaste as an abrasive and foaming agent.
- It is utilized in the manufacture of detergents, soaps, and paper.
- It is also utilized to produce water glass (sodium silicate), borax, sodium phosphate, and a range of other salt compounds.
Do Check Out:
Comments