Question

Arrange the liming materials based on their decreasing neutralizing value of CCE(%)
(A).Dolomite
(B).Basic slag
(C). Calcite
(D).Calcium oxide
Choose the correct answer from the options given below:

• A. (D), (A), (C), (B).
• B. (A), (B), (C), (D).
• C. (B), (A), (D), (C).
• D. (C), (B), (D), (A).

Hint:

To determine CCE, write the balanced chemical neutralization equations.
Oxide forms (\( \text{CaO} \)) always have higher CCE values than hydroxide forms (\( \text{Ca(OH)}_2 \), CCE 136%), which in turn have higher values than carbonate forms (\( \text{CaCO}_3 \), CCE 100%).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Liming materials are basic compounds applied to acid soils to raise the soil pH.
The effectiveness of a liming material is quantified by its Calcium Carbonate Equivalent (CCE), also known as its neutralizing value.
The CCE is the neutralizing capacity of a material expressed as a percentage of the neutralizing capacity of pure calcium carbonate (\( \text{CaCO}_3 \)), which is assigned a reference value of 100%.

Step 2: Detailed Explanation:
The neutralizing value of liming materials depends on their molecular weight and chemical composition.
Materials with lower molecular weights per mole of neutralizing basicity have higher CCE values.
Let us analyze the standard CCE values of the given materials:
- (D) Calcium oxide (\( \text{CaO} \)): Also known as burnt lime.
It has a very low molecular weight (56 g/mol) compared to calcium carbonate (100 g/mol).
Its CCE is approximately 179%.
- (A) Dolomite (\( \text{CaMg(CO}_3)_2 \)): Contains both calcium and magnesium carbonates.
Because magnesium has a lower molecular weight than calcium, dolomite has a higher neutralizing capacity per unit weight than pure calcite.
Its CCE is approximately 109%.
- (C) Calcite (\( \text{CaCO}_3 \)): Pure calcium carbonate.
It is the standard reference material with a CCE defined as 100%.
- (B) Basic slag: A byproduct of steel manufacturing containing calcium silicates.
It has a relatively low neutralizing capacity, with a CCE typically ranging from 50% to 70%.
Therefore, arranging these materials in decreasing order of CCE yields:
\[ \text{Calcium oxide (D) } [179\%] > \text{ Dolomite (A) } [109\%] > \text{ Calcite (C) } [100\%] > \text{ Basic slag (B) } [50\text{--}70\%] \]
This matches the sequence (D), (A), (C), (B), corresponding to Option (A).

Step 3: Final Answer:
The correct decreasing sequence of neutralizing values is (D), (A), (C), (B).