Question

Given below are two statements:
Statement (I): The gravitational potential is independent of the relative elevation and is dependent on chemical and pressure conditions of soil water.
Statement (II): Osmotic potential can be defined as the amount of work that a unit quantity of water in an equilibrium soil water system is capable of doing when it moves to another equilibrium system identical in all respects except that there are no solutes.
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

Gravitational potential depends only on elevation; chemical and pressure effects belong to other potential components.

Answer 1

The Correct Option is D

Soil water potential is made up of separate components, and each one depends on a specific factor only.
Gravitational potential $Z_w$ depends only on how high or low the water is compared to a fixed reference level; it does not change because of dissolved salts or pressure. So the claim in Statement (I) that gravitational potential does not depend on elevation but depends on chemical and pressure conditions is the wrong way round, making it false.
Now check Statement (II) by definition: osmotic potential measures the extra work a parcel of water can do because a nearby system has no solutes, everything else being equal. That is precisely what Statement (II) describes, so it is true.
\[\boxed{\text{Statement (I) is incorrect, Statement (II) is correct, so option 4 is correct.}}\]