Which of the following is not present in cement ?

Options

A. Gypsum
B. Clay
C. Almina
D. Alum

Answer

To determine which of the following is not present in cement, we need to analyze the typical components of cement and their respective compositions. Here’s a step-by-step breakdown:

### Step 1: Identify the Common Components of Cement
Cement is primarily composed of several key components. The main constituents include:
- Quicklime (CaO)
- Silica (SiO2)
- Alumina (Al2O3)
- Ferric oxide (Fe2O3)
- Minor oxides (such as magnesium oxide, sodium oxide, potassium oxide)

### Step 2: Analyze Each Option
Now, let’s analyze the options provided in the question to see which one is not typically found in cement.

1. **Quicklime (CaO)**: This is a major component of cement, making up about 61.69% of its composition.
2. **Silica (SiO2)**: This is also a significant component, constituting around 18.24% of cement.
3. **Alumina (Al2O3)**: Present in cement, with a composition of about 4.8%.
4. **Ferric Oxide (Fe2O3)**: This is present as well, making up about 1.8% of cement.
5. **Gypsum**: While not listed as a percentage, gypsum is used in the production of cement and is present in the final product.
6. **Clay**: Contains silica and alumina, and is also a component of cement.
7. **LM (Double salt of potassium sulfate and aluminum sulfate)**: This is not a component of cement.

### Step 3: Conclusion
Based on the analysis, the component that is not present in cement is **LM** (the double salt of potassium sulfate and aluminum sulfate).

Thus, the correct answer to the question is **LM**.

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