Volumetric Analysis practical

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Volumetric Analysis Practical

To determine the pH of commercially supplied 32% Hydrochloric acid solution.

Investigative question

Can the pH of an acid which is Hydrochloric acid be calculated by using titration with a standardized base solution of Sodium Hydroxide?

Hypothesis

That the pH of the hydrochloric acid solution can be calculated using titration with a standardised sodium hydroxide base solution as long as concentration and temperature of base solution remain constant.

Variables

Independent variable

Volume of base (sodium hydroxide) needed to titrate the acid solution

Dependant Variable

Volume of acid (hydrochloric acid) placed in beaker to be titrated.

Controlled variables

• Concentration of base

• Temperature of chemicals

• Same indicator used

• Chemicals obtained from the same bottles

• Same measuring apparatus used

Apparatus

• 2x burette

• 2x retort stand

• 2x clamp

• 6x conical flask

• 2x round bottom flask

• 2x pipette

• 1x measuring cylinder

• 1x spatula

• 1x electronic scale

• 2x beaker

• 1x Erlenmeyer flask

• 4x 250ml volumetric flask

• 10ml Bromothymol blue

• 3x oxalic acid crystals

• 3x Sodium hydroxide pellets

• 1 Bottle Hydrochloric acid solution

• 1x Thermometer

• 1x video camera

• 1x dropper

Diagram

Method

Safety precautions

1. Plugging the beakers containing chemicals

2. Using tongs to pour chemicals

3. Keeping eyes and nose away from the opening of the beakers

4. Standing away from the work table when not working on the experiment

5. Wear thin rubber gloves

6. Wear a lab coat

7. Remove ties

8. Wear safety goggles

9. Be aware of acid burns from hydrochloric acid.

Accuracy precautions

1. Using the same measurin...

... middle of paper ...

...ransfer of substances like sodium chloride from a measuring beaker to a flask in which to conduct the experiment results in trace particles being left in the beaker. This alters the number of moles in the solution altering concentration and therefore results.

Bibliography

• Acid Base Titration (Theory) : Inorganic Chemistry Virtual Lab : Chemical Sciences : Amrita Vishwa Vidyapeetham Virtual Lab . 2014. Acid Base Titration (Theory) : Inorganic Chemistry Virtual Lab : Chemical Sciences : Amrita Vishwa Vidyapeetham Virtual Lab . [ONLINE] Available at: http://amrita.vlab.co.in/?sub=2&brch=193&sim=352&cnt=1. [Accessed 25 May 2014].

• Aqueous Acid-Base Equilibria and Titrations. Levie, Robert De. New York : Oxford University Press, 1999.

• Reactions of Acids and Bases in Analytical Chemistry. Hulanicki, A. and Masson, M.R. New York: Halsted Press, 1987.

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