Universiti Tunku Abdul Rahman (kampar Campus) Faculty Of Science, Engineering,

Universiti Tunku Abdul Rahman (Kampar Campus) Faculty of Science, Engineering, and Technology Bachelor of Science (Hons) Biotechnology Year 1 Semester 2 Laboratory 1B (UESB 1212) (II) The Properties of Matter Lecturer: Ms. Chew Yin Hoon Student’s Name: Cheah Hong Leong Student’s ID: 08AIB03788 Partner’s Name: Chong Shi Fern Partner’s ID: 08AIB02580 Experiment No. 6 Title: Extraction: Extraction with Acid and Alkali Date: 13 March 2009

Title: Extraction: Extraction with Acid and Alkali

Objective: –

To determine the percentage of recovery of the benzoic acid and dichlorobenzene extracted from the ether solvent and aqueous solvent.

–

Determine the melting point of the extracted dichlorobenzene.

Results: Weight of starting dichlorobenzene = 1.0178g Weight of starting benzoic acid = 1.0016g Volume of ether = 40 ml Volume of NaOH added before first separation = 20 ml Volume of NaOH added before second separation = 10 ml In aqueous solution, Weight of filter paper = 0.9817g Weight of filter paper and recovered benzoic acid solid = 2.4670g Weight of recovered benzoic acid solid = 1.4799g In organic solution, Weight of watch glass = 28.8334g Weight of watch glass and recovered dichlorobenzene = 28.9601g Weight of recovered dichlorobenzene = 0.1267g Melting point of dichlorobenzene = 53 oC Analysis and Calculation: Percentage of recovery= Weight of recovered solidWeight of starting solid x 100%

Percentage of recovery of benzoic acid = (1.4799g/1.0016g) x 100% = 147.75% Percentage of recovery of dichlorobenzene = (0.1267g/1.0178g) x 100% = 12.45%

Discussion: Percentage of recovery of benzoic acid was more than 100% which is impossible. The most possible reason causing this was the incomplete hydration of benzoic acid. The weight of the benzoic acid solid obtained was not the actual weight of the recovered benzoic acid. Most of the weight obtained was contributed by unhydrated water that still remained in the solid.

In contrast to the percentage of recovery of benzoic acid, percentage of recovery of dichlorobenzene was too low, only 12.45%. Most of the starting dichlorobenzene was not recovered from the solution. Another possible reason that leads to this percentage was the drying of the solid in fame hood. During the drying of this solid in fame hood, some of the solid in watch glass was moved out of the watch glass by the air flow in fame hood.

Conclusion: The percentage of recovery of benzoic acid was unknown. The percentage of recovery of dichlorobenzene was 12.45% The melting point of dichlorobenzene was 53 oC.