Problem 71 - Objective Biology for NEET

Question

Which of the following is correct about imbibitions? (a) It requires \(\psi \omega\) gradient between the absorbent and the liquid imbibed. (b) It requires affinity between the absorbent and the liquid. (c) Imbibition pressure is produced by the swelling of wood and in turn used by prchistoric man to split rocks and boulders. (d) All the above

Step-by-Step Solution

Answer

The correct options about imbibition are (b) it requires affinity between the absorbent and the liquid, and (c) imbibition pressure is produced by the swelling of wood and in turn used by prehistoric men to split rocks and boulders.

Step 1: Understanding Imbibition

Imbibition is a special type of diffusion when water is absorbed by solids-colloids causing an enormous increase in volume. Examples include the absorption of water by seeds and dry wood. Hence, this helps in understanding what property/properties imbibition should possess.

Step 2: Evaluate each option

(a) Imbibition does not require a \(\psi \omega\) gradient between the absorbent and the liquid imbibed, but a diffusion gradient. So, this option is incorrect. \n (b) Imbibition does indeed require an affinity between the absorbent and the liquid. That's why substances with similar properties attract each other. So, this option is correct. \n (c) Imbibition does indeed result in increased volume and pressure. This is observed in wood swelling when water is imbibed, and this method of splitting rocks and boulders by increasing imbibition pressure was indeed used by primitive men. Hence, this option is correct. \n Therefore, upon evaluating, we find that option (a) is incorrect.

Step 3: Determine the Correct Option

Since options (b) and (c) are correct while option (a) is incorrect, the correct answer cannot be (d) 'All the above'. Therefore, the correct answer should be that 'imbibition requires affinity between the absorbent and the liquid' and 'imbibition pressure is produced by the swelling of wood and in turn was used by prehistoric men to split rocks and boulders'.

Key Concepts

Diffusion

Imbibition is closely linked to the process of diffusion. Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration. In the case of imbibition, solid substances, such as dry seeds or wood, absorb water predominantly due to diffusion gradients.
This causes the substances to swell as water diffuses into their porous structures.

In simple terms, think of diffusion as the natural process where things try to 'spread out evenly'. When water molecules encounter dry wood, they move into the wood's tiny spaces until they are evenly distributed. This movement is driven by the diffusion gradient, which relies on the difference in concentration levels between the absorbent and the surrounding liquid.

• Diffusion must occur for imbibition to take place.
• The absorbent material should have spaces for diffusion to happen effectively.

This is why diffusion is a key concept in understanding how imbibition works.

Affinity between absorbent and liquid

For imbibition to successfully occur, there must be an affinity between the absorbent and the liquid. This affinity refers to the chemical attraction between molecules of the absorbent and molecules of the liquid.
When rocks and plants absorb water, it's primarily because these structures possess components that are naturally inclined to bind with water molecules.

In practice, this means that substances that need to undergo imbibition should be compatible with the water or liquid they are absorbing.

• Having a similar chemical structure or polarity between the absorbent and the liquid enhances the binding process.
• A strong affinity means better and faster absorption and swelling.

Thus, understanding the role of affinity is crucial in recognizing how differential absorption rates can occur based on the relationship between the absorbent and the liquid.

Imbibition pressure

When imbibition takes place, it generates pressure, commonly known as imbibition pressure. This pressure results from the volume increase when a solid absorbs water or any liquid.
Historically, this natural force was utilized by prehistoric humans, who harnessed the power of swelling wood to cleave stones and boulders.

Here's how it works:

• The absorbed water causes the wood to expand.
• As more water is imbibed, the internal pressure builds up.

This pressure, if sufficiently high, is capable of exerting force substantial enough to split rocks apart. This led to the use of such methods in ancient engineering and construction.
Thus, imbibition pressure is not only a fascinating natural phenomenon but also a practical tool historically used by early civilizations.