To Preparation and Standardization of 0.1 N HCl utilizing sodium carbonate (also comprehended as washing soda, soda ash, and soda crystals) as the primary standard (Acid-base titration).
Prerequisites for preparation and standardization of 0.1 N HCL:
Glasswares: Burette, stand for burette, a conical flask, volumetric pipette to makeup volume, beaker, volumetric flask, funnel, glass rod, washed bottle, etc.
Chemicals: Concentrated HCl, sodium carbonate (Na2CO3), methyl orange indicator, etc.
To titrate the hydrochloric acid solution a methyl orange indicator can be used against the sodium carbonate solution. When titrating a slightly acidic solution with a weak base, the endpoint is also slightly acidic. When a weak acid is titrated with a strong base, the solution is somewhat alkaline because the salt produced is partially hydrolyzed.
The reaction of sodium carbonate with hydrochoric acid is following:
Na2CO3(aq) + 2HCl(aq) → 2NaCl(aq) + CO2(g) + H2O(l)
CO32-(aq) + 2H+(aq) → CO2(g) + H2O(l)
In an acid-base titration process, the portion of acid becomes chemically equivalent to the quantity of base present. The solution becomes neutral when a strong acid and a strong base are titrated concurrently.
How to prepare 0.1 N HCl:
To prepare 0.1 N HCL, Dilute 8.50 ml of HCL with distilled water to make up the volume to 1000 ml.
How to prepare 0.1M Na2CO3 solution:
To prepare 0.1M Na2CO3 solution, Take 1.06 gm of sodium carbonate and well mixed in 50 ml of distilled water in a given volumetric flask, and properly mix it to get dissolved and finally make it up to 100 ml volume.
- Make sure all the glassware should be cleaned properly before use as per standard laboratory procedure.
- Rinse the burette with distilled water before its use, also rinse with a small portion of titrant solution to avoid contamination of the solution.
- To remove the air bubble from the burette, Take the solution of titrant in a clean and dry beaker then fill the burette using the funnel, and finally set the reading to zero.
- Now by using a pipette, transfer the 5 ml of prepared solution of sodium carbonate (Na2CO3) and pour it into a conical flask. now add one or two drops of methyl orange indicator drop by drop.
- Now Start the titration by addition of Hydrochloric acid (HCL) drop by drop followed by stirring continuously, until the solution turns pale pink.
- Now take the solution and Boil it until the color turns yellow again, then cool and titrate similarly until a faint pink color is no longer impacted by boiling.
- Repeat the titration process three times to get a better result and same time take the reading from the pipette. Calculate the mean to find out the normality of the HCL solution.
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Calculations for 0.1N HCL:
N x V = wt. / eq. wt. x 1000
N denoted for normality of HCl to be calculated
V denoted the volume of HCl used
Wt. is denoted for the weight of Na2CO3
eq. wt is denoted for equivalent Weight of Na2CO3
The prepared HCl solution was discovered to have the following strength:_____N.