Question

Given below are two statements:
Statement (I): The porosity of a soil cannot exceed 100 per cent.
Statement (II): The degree of saturation cannot be zero per cent.

In light of the above statements, choose the most appropriate answer from the options given below.

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

Hint:

Think of oven-dried soil to test whether degree of saturation can really be zero.

Answer 1

The Correct Option is C

Step 1: Picture the three-phase diagram of a soil element, split into solids, water and air. Above the solid layer sits the void space, shared between water and air in any proportion from all air to all water.
Step 2: Porosity only compares the void block to the whole sample block. Since the void block sits inside the total sample and cannot spill outside it, the ratio of void volume to total volume is capped at 1, or 100 percent, reached only when the entire sample is void space with nothing solid in it. So porosity cannot read above 100 percent, which makes Statement (I) correct.
Step 3: Degree of saturation only looks inside the void block, comparing how much of that void space is filled with water versus air. If the sample is bone dry, the entire void space is air and none of it is water, so the water share of the voids is 0 percent.
Step 4: A completely dry soil is a real, common situation, such as desert sand or an oven dried lab sample, so a 0 percent degree of saturation is physically possible and not forbidden. Statement (II) says this can never happen, and that claim does not hold up.
Step 5: Putting it together, Statement (I) stands as true and Statement (II) fails as false.
\[\boxed{\text{Statement (I) is true but Statement (II) is false}}\]