Virtual Lab Giter paper with the precipitate is first incinerated on a Bunsen bu

Question

Virtual Lab Giter paper with the precipitate is first incinerated on a Bunsen burner by a low flame and then transferred to an etectric burner ·Observation: Observations of Experimental Procedure In this section, make observations for every step of the procedure The given barium chloride solution is made up to 100ml. in a standard flask. The crucible is transferred to desiccator and cooled Observation . When cold, the crucible is weighed. . 20ml of solution is pipetted into a 250 mL beaker Heating, cooling and weighing are repeated till concordant values are obtained Observation: bout SmL 2N HC is added and diluted to 150mL with distilled water Observation Calculation Mass of crucible ld -(a) s Mass of crucible lid + Barium sulfate (b)g . The solution is heated to boiling and a hot solution of 4N H:SOs (10 15mL) is added drop by drop with constant stirring till the precipitation is complete Observation . Th . Observation: e solution containing the precipitate is heated in a water bath for 5 minutes Mass of Barium sulfate (b-a) g ·The precipitate is allowed to stand for an hour 233.36g of barium sulfate contain 137.36 g of barium Mass of barium in (b-a) g of Barium sulfate Therefore, Mass of Barium in the whole of the given solution The clear solution is decanted through an ashless filter paper (whatman No. 40) . The precipitate is washed with hot distlled water to free sulfate ions. ·Observation: ·The particles adhering to the sides of the beaker and glass rod are removed hy policeman. Observation: . Finally the precipitate is washed once again. " Observation: Result: The dried filter paper is folded and placed in a crucible which has been previously Mass of Barium in the whole of the given solution weighed. . Observation

Explanation / Answer

Analysis of barium

Here, barium analysis is done by converting the barium to barium sulfate precipitate

The chemical reaction occuring would be,

Ba2+ (aq) + H2SO4 (aq) ---> BaSO4 (ppt) + 2H+ (aq)

The precipitated BaSO4 is incinerated in oven and the mass of final precipitate is obtained.

1 mole of Ba2+ would give 1 mole of BaSO4 formation

Observation : The precipitate is obtained as white solid.

moles of BaSO4 formed = final mass of BaSO4 precipitate/233.36 g/mol

moles of barium (Ba2+) = moles of BaSO4

mass of Barium in the sample = moles of Ba2+ x 137.36 g/mol

This mass obtained is for 20 ml sample

So,

Total mass of barium in the entire sample = mass of Barium from above x 100/20

[Formulas used, moles = grams/molar mass]

So feeding the values for the mass of precpitate obtained (starting with 20 ml sample solution) we can calculate the mass of barium in the original sample solution (100 ml).

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