Page 44 - Chemistry - XI

Materials Required

Burette (50 mL), pipette (25 mL), conical fl ask (250 mL), burette stand, funnel, white glazed tile, measuring
fl ask (250 mL), and oxalic acid

Procedure

1. We will prepare 250 mL of 0.1 M oxalic acid solution.
2. Weigh empty watch glass with the help of a chemical balance.
3. Take approximate amount of a substance in a watch glass and weigh exactly 3.15 g of oxalic acid
crystals by using a chemical balance.
4. Take a measuring fl ask of 250 mL, washed thoroughly with water.

5. Transfer the substance from the watch glass into the fl ask with the help of a funnel. Add water with the
help of a wash bottle.
6. Wash the funnel several times with distilled water without removing the funnel from the fl ask by using
a wash bottle. Add water slowly so that it may not exceed the volume mark of the fl ask.
7. Remove the funnel and shake the fl ask till the solid completely dissolves.

8. Make up the solution up to the mark by adding distilled water with the help of a wash bottle and shake
it after closing the fl ask with the stopper.
9. This is the standard solution of oxalic acid which has 0.1 M concentration.

Result

0.1 M standard solution of hydrated oxalic acid has been prepared by the given method.

EXPERIMENT - 16

Objective
Determination of the strength of a given sodium hydroxide solution by titrating it against a standard solution
(M/10) of oxalic acid.

Materials Required

Burette (50 mL), pipette (25 mL), conical fl ask (250 mL), burette stand, funnel, white glazed tile, measuring
fl ask (250 mL), and oxalic acid (M/10)

Procedure

1. We will prepare 250 mL of 0.1 M oxalic acid solution as discussed in Experiment - 1.
2. Rinse a clean burette with oxalic acid solution and fi ll it with the oxalic acid solution.
3. Remove the air gap and set the burette reading at zero.
4. Pipette out 25 mL of given NaOH solution in a conical fl ask and add 3–5 drops of phenolphthalein

indicator into it.
5. Titrate the solution with oxalic acid until pink colour just disappears.
6. Repeat the titration till two concordate readings are obtained.
6. Repeat the titration till two concordate readings are obtained.

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