Agard Block: To investigate the effect of a differing Surface Area: Volume ratio on the rate of diffusion.

... Romin Parekh X - B Biology Lab Experiment Aim To investigate the effect of a differing Surface Area: Volume ratio on the rate of diffusion. Theory Agar is a polysaccharide which can be obtained by seaweed or red algae. It is a base i.e. it has a pH higher than 7 where 7 on the pH scale is the pH of pure water. When the agar block is placed in the test tube containing the acid, Hydrochloric Acid, diffusion occurs. Diffusion is the movement of particles from a high concentration to a low concentration. Here the acid molecules are in high concentration in the test tube and so diffuse into the agar block for to maintain an equal concentration throughout the acid and the agar block. When diffusion takes place, the agar block loses its property of being a base into a substance of neutral pH which 7. Due to the presence of an indicator Phenolphthalein,

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