Question:hard

Select the correct sequence of increasing size (thickness) of clay minerals
(A) Montmorillonite
(B) Chlorite
(C) Kaolinite
(D) Illite
Choose the correct answer from the options given below:

Show Hint

Montmorillonite is the thinnest clay mineral and kaolinite is the thickest.
  • (B), (A), (C), (D).
  • (A), (D), (B), (C).
  • (C), (B), (A), (D).
  • (D), (C), (A), (B).
Show Solution

The Correct Option is B

Solution and Explanation

Rank the four minerals using their known specific surface area instead, since thickness and specific surface area move in opposite directions (thinner particles expose more surface per unit mass).
Montmorillonite has the highest specific surface area (700 to 800 square meters per gram), so it must have the thinnest, smallest particles.
Illite has a much lower specific surface area than montmorillonite, so its particles are thicker.
Chlorite behaves like a non-expanding 2:1:1 mineral with a slightly lower surface area than illite, meaning its particles are a bit thicker again.
Kaolinite has the lowest specific surface area of the four (about 10 to 20 square meters per gram), meaning it has the thickest, largest particles.
Arranging from lowest surface area (thickest) is the reverse of the required increasing size order.
\[\boxed{\text{Montmorillonite, Illite, Chlorite, Kaolinite}}\]
Was this answer helpful?
0