7.3.2 - Laboratory Activity : Preparation of solution of certain concentration using the dilution method

Laboratory Activity 7.3.2: Preparation of solution of certain concentration using the dilution method

Aim: To prepare standard solution of hydrochloric acid, 0.2mol dm^-3 , 0.02mol dm^-3 and 0.002mol dm^-3 through the dilution of hydrochloric acid standard solution, 2mol dm^-3.

Material: » Hydrochloric acid 2mol dm-3 » Distilled water

Apparatus: » Volume flask (100cm3) » Pipette (10cm3) with pump » Filter funnel

Procedure:

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	►	1. 100cm3 volumetric flask is used in this experiment. Determine the amount of volume of hydrochloric acid of that need to used to produce a diluted hydrochloric acid of 0.2mol dm-3 by using the dilution equation. $\begin{array}{c}{M}_1{V}_1\mathrm{=}{M}_2{V}_2\end{array}$ $\begin{array}{c}2\mathrm{\times }{V}_1\mathrm{=}0.2\mathrm{\times }100\end{array}$ $\begin{array}{c}{V}_1\mathrm{=}\frac{0.2\mathrm{\times }100}{2}\end{array}$ $\begin{array}{c}{V}_1\mathrm{=}10{\mathit{cm}}^3\end{array}$ 2. 10cm3 of 2mol dm-3HCl is transferred from the given solution into a 100cm3 volumetric flask by using pipette. 3. Distilled water is added to the 100cm3 mark; the flask is then closed and inverted for few times until the solution is well mixed. A 0.2mol dm-3HCl solution is obtained. 4. To prepare 100cm3 of 0.02mol dm-3HCl, step 2 and 3 are repeated using 10cm3 of 0.2mol dm-3HCl. 5. To prepare 100cm3 of 0.002mol dm-3HCl, step 2 and 3 are repeated using 10cm3 of 0.02mol dm-3HCl.

Results:

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Molarity of initial acid M1, mol dm-3 Initial volume used V1/cm3 Final volume used V2/cm3 Molarity of final acid M2, mol dm-3 2.0 10 100 0.2 0.2 10 100 0.02 0.02 10 100 0.002

Conclusion:

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Hydrochloric acid of varying molarities can be prepared by diluting a standard solution, 2 mol dm-3.

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