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Introduction to Experiment
Imbibition is the absorption of one substance by another, in particular the uptake of water by a plant or seed. It is a special type of diffusion that takes place when liquid is absorbed by the imbibant’s colloids, causing an increase in volume. The substance that undergoes imbibition is called the imbibant, and the liquid is called the imbibate. In this experiment, the process of imbibition is demonstrated by soaking imbibants such as raisins and seeds in water.
Experiment Procedure
In two measuring cylinders, A and B, 30 mL of water is added, and the water level is recorded.
25 g of raisins and seeds are taken and transferred to the measuring cylinders A and B, resulting in an increase in water level to 42 mL and 48 mL respectively.
The difference in the water level is 12 mL for raisins and 18 mL for seeds, these values are denoted by X.
The imbibants, i.e., raisins and seeds, are soaked in water for 2 hours. During this process, water molecules are absorbed by the imbibant’s hydrophilic colloids, causing an increase in the volume of raisins and seeds. This process of water absorption is called imbibition, which is a special type of diffusion.
Water is decanted from both measuring cylinders after soaking. The soaked raisins and seeds are removed, and any excess water is wiped away with blotting paper.
After the blotting process, 30 mL of water is again added to both measuring cylinders.
The soaked raisins and seeds are again added to the measuring cylinders, which results in an increase in water level to 48 mL for raisins and 51 mL for seeds; these values are denoted by X.
The difference in the water level is 18 mL for raisins and 21 mL for seeds; these values are denoted by Y.
The increase in the volume of raisins is calculated by the formula Z = Y – X, i.e., 6 mL for raisins and 3 mL for seeds.
The percentage of water imbibed is calculated by the formula Z/X x 100; thus, for raisins, the percentage of water imbibed is 50%, and for seeds, it is 16.7%.
The percentage of water imbibed can also be calculated by knowing the mass of the raisins and seeds before and after soaking in water.
FAQs about Distribution of Stomata on Leaf Surfaces
Q1. Define imbibition.
Ans. Imbibition is the absorption of one substance by another, in particular, the uptake of water by a plant or seed. It is a special type of diffusion that occurs when liquid is absorbed by the imbibant’s colloids, causing an increase in volume. The substance that undergoes imbibition is called the imbibant, and the liquid is called the imbibate.
Q2. Concerning imbibition, what are surface colloids?
Ans. Surface colloids are hydrophilic solid particles that absorb water or any other hypotonic solution, causing the volume of the imbibate to increase.
Q3. Why seeds and raisins are considered for the imbibition experiment?
Ans. Seeds and raisins are taken for the experiment because, unlike substances like stones or feathers, they have a tendency to absorb water and increase in volume.
Q4. Does imbibition occur when the raisins are soaked in hypertonic solutions?
Ans. Imbibition occurs when the imbibant is soaked in hypotonic solutions, but it does not occur when kept in a hypertonic medium, such as absolute alcohol, because the diffusion of water molecules occurs from the imbibant’s interior to the exterior solution, resulting in shrinkage of the imbibant.
Q5. Describe the formula to calculate the percentage of water imbibed.
Ans. The increase in the volume of imbibant is calculated by the formula Z = Y – X, where X is the difference in water level before soaking the imbibant and Y is after soaking. The percentage of water imbibed is calculated by the formula Z/X x 100.
JEE Main