Laboratory Report Exp 1 CHM 256 PDF

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LABORATORY REPORTBASIC ANALYTICAL CHEMISTRY(CHM 256)EXPERIMENT:Standardization of HCl solution with Na 2 CO 3 PrimaryStandardNAME: Putri Nurnajwa Sabrina Binti Megat Budiman AffendiMATRIX NUMBER: 2019288752PROGRAMME: AS 116GROUP: AS 116 2DDATE OF EXPERIMENT:NAME OF LECTURER: MADAM MAZNI BINTI MUSAIN...

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LABORATORY REPORT BASIC ANALYTICAL CHEMISTRY (CHM 256)

EXPERIMENT: Standardization of HCl solution with Na2CO3 Primary Standard

NAME: Putri Nurnajwa Sabrina Binti Megat Budiman Affendi MATRIX NUMBER: 2019288752 PROGRAMME: AS 116 GROUP: AS 116 2D1 DATE OF EXPERIMENT: NAME OF LECTURER: MADAM MAZNI BINTI MUSA

INTRODUCTION Pure sodium carbonate is a non-hygroscopic primary standard reagent. A standard solution prepared by dissolving a known amount of the solid Na 2CO3 in a fixed volume can be used to standardize other acid solutions. The aim of the experiment is to prepare a standard solution of exact concentration which can later be used to standardize other solutions. HCl is not a primary standard. Thus, after a dilute HCl solution is prepared, it has to be standardized with a primary standard solution in order to determine its concentration accurately. In this experiment a standard Na 2CO3 solution and a dilute HCl solution will be prepared. The HCl solution will later be standardized against the Na 2CO3 solution. The reaction between HCl and Na2CO3 is as follows. 2 HCl + Na2CO3  2NaCl + H2O + CO3

OBJECTIVES  

To determine the exact molarity of a hydrochloric acid solution. To determine the volume of HCl used for titration.

APPARATUS i. ii. iii. iv. v. vi.

100 mL beaker 250 mL volumetric flask 250 mL conical flask 25 mL pipette Burette Retort stand

CHEMICALS i. ii. iii.

Na2CO3 Concentrated HCl Methyl orange indicator

PROCEDURE

a. Preparation of 0.06 M Na2CO3 solution. i.

Weighed accurately about 1.33 g of Na2CO3. The exact mass of the Na2CO3 was recorded.

ii.

The Na2CO3 was dissolved in about 50 mL water in a 100 mL beaker.

iii.

Transferred the solution into a 250 mL volumetric flask. The beaker was rinsed with distilled water.

iv.

Distilled water was added to the mark. Stopper the flask.

v.

Shake it by turning it upside down a few times to make sure the solution homogeneous.

b. Preparation of a dilute HCl solution. i.

2.2 mL of concentrated HCl was transferred into a 250 mL beaker that contain a little water.

ii.

Diluted the acid to approximately 250 mL with distilled water.

c. Standardization of the dilute HCl solution. i.

Filled a burette with the dilute HCl solution prepared in (b) above. The initial burette reading was recorded.

ii.

25.0 mL of the standard Na2CO3 were pipetted into a 250 mL conical flask. 2-3 drops of methyl orange indicator were added.

iii.

Titrated the Na2CO3 in the conical flask with the HCl from the burette slowly while shaking the flask until the indicator colour change from yellow to red. The burette reading at the end point of the titration was recorded.

iv.

The titration was repeated 3 times. All the data were recorded.

v.

Calculated the exact molarity of the HCl solution.

RESULTS

Your result should contain the following:

1. Weight of Na2CO3 used =

1.33

g

2. Standardization of HCl with Na2CO3 solution.

Initial burette reading (mL) Final burette reading (mL) Volume of HCl used (mL)

Rough 0

1 0

2 0

14.5

14.5

14.5

14.5

14.5

14.5

3. Calculate the molarity of the HCl solution. moles of solute Molarity ( M )= liters of solute RMM of HCl: 1 + 35.5 = 36.5 g/mol RMM of Na3CO3: 23(2) + 12 + 16(3) = 106 g/mol No. of mole Na2CO3: 1.33 g =0.013 mol 106 g mol ˉ ¹ 2 mol HCl

: 1 mol Na2CO3

0.026 mol HCl : 0.13 mol Na2CO3 = 0.026 mol Molarity of HCl solution: 0.026 mol =0.104 M 0.25 L

QUESTION Calculate the molarity of the concentration of the concentrated HCl. Average of HCl used = 14.5 mL Concentration of HCl used = Concentration of HCl (concentrated) M1V1 = M2V2

DISCUSSION

(0.104) (0.0145) = (M2) (0.0022)

M2 = 0.69 M

Titration is a method used to a known volume of another solution of unknown concentration until the reaction reaches neutralization. It is used to determine concentration of an identified analyte. For this experiment, titration method involved with Hydrochloric acid (HCl) and Sodium Carbonate (Na2CO3). When a weak base was titrated with strong acid, the solution is slightly acidic at the end of the point. It is because, the salt formed will be hydrolysed to a certain extent. From the reaction between hydrochloric acid and sodium carbonate, sodium chloride, carbon dioxide and water are formed. 2 HCl + Na2CO3  2NaCl + H2O + CO3 In this experiment, our result for titration for standardization of HCl solution with Na2CO3 primary standard were very accurate. This titration was repeated three times to get accurate result. We used 0.104 M of HCl and Na2CO3 for the titration and methyl orange as the indicator. The main aim for the experiment is to determine the exact molarity of a hydrochloric acid solution. So, after the titration, we got to determine the exact value of HCl molarity. By using mass of Na2CO3 given, we can find out number of moles for HCl and the molarity of the HCl.

CONCLUSION From this experiment, Standardization of HCl solution with Na2CO3 Primary Standard, we able to find true to count molarity of a hydrochloric acid solution by using a few of formulas and involved titration method. All of the method and calculations involved in this experiment were accepted. Moreover, no error detected in this experiment.

REFERENCES 1) Libretexts. (2019, June 23). Titration. 2) A. (2019, November 13). Titration of Hydrochloric Acid against Standard Sodium Carbonate....