Question

Arrange the given minerals based on their cation exchange capacity:
A. Kaolinite
B. Montmorillonite
C. Nontronite
D. Vermiculite
E. Illite
Choose the correct answer from the options given below:

• A. D, A, C, D, E
• B. D, B, C, A, E
• C. D, B, E, C, A
• D. D, B, C, E, A

Hint:

CEC of clay minerals:
- Vermiculite: 150-200 cmol/kg (Highest)
- Montmorillonite: 80-150 cmol/kg
- Nontronite: 60-100 cmol/kg
- Illite: 20-40 cmol/kg
- Kaolinite: 3-15 cmol/kg (Lowest)

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Cation exchange capacity (CEC) is the ability of soil minerals to hold and exchange cations.

Step 2: Detailed Explanation:
The CEC of clay minerals varies based on their structure:
- Vermiculite (D): Very high CEC (150-200 cmol/kg).
- Montmorillonite (B): High CEC (80-150 cmol/kg).
- Nontronite (C): Medium to high CEC (60-100 cmol/kg).
- Illite (E): Medium CEC (20-40 cmol/kg).
- Kaolinite (A): Low CEC (3-15 cmol/kg).
Thus, the decreasing order of CEC is: Vermiculite > Montmorillonite > Nontronite > Illite > Kaolinite.
This corresponds to D, B, C, E, A.

Step 3: Final Answer:
Thus, the correct arrangement is D, B, C, E, A.
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