Consider the following statements : Statement I: In the context of effect of water on rocks, chalk is known as a very permeable rock whereas clay is known as quite an impermeable or least permeable rock. Statement II : Chalk is porous and hence can absorb water. Statement III : Clay is not at all porous. Which one of the following is correct in respect of the above statements?
- ABoth Statement II and Statement III are correct and both of them explain Statement I
- BBoth Statement II and Statement III are correct but only one of them explains Statement I
- COnly one of the Statements II and III is correct and that explains Statement ICorrect
- DNeither Statement II nor Statement III is correct
Explanation
Statement I: Correct. Chalk is indeed very permeable (allows water to pass through) while clay is quite impermeable (prevents water movement).
Statement II: Correct and explains Statement I. Chalk is porous with numerous interconnected pore spaces that allow water absorption and movement, making it highly permeable despite being a solid rock.
Statement III: Incorrect. Clay is actually quite porous, but its pores are extremely small (micropores) and poorly connected, which prevents water movement. It's the size and connectivity of pores, not the absence of porosity, that makes clay impermeable.
Only Statement II correctly explains the permeability difference, as chalk's effective porosity allows water flow while clay's microporous structure restricts it.
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