A major constituent of portland cement is?

Options

A. Silica
B. Alumina
C. Iron oxide
D. Magnesia

Answer

To solve the question "A major constituent of Portland cement is?", we can follow these steps:

### Step 1: Understand what Portland cement is
Portland cement is the most common type of cement used globally as a basic ingredient in concrete and mortar. It is essential to know its composition to answer the question.

**Hint:** Research the definition and uses of Portland cement to grasp its significance in construction.

### Step 2: Identify the major components of Portland cement
Portland cement consists of several key chemical compounds. The main constituents include:
- Silica (SiO2)
- Calcium oxide (CaO)
- Alumina (Al2O3)
- Iron oxide (Fe2O3)
- Magnesium oxide (MgO)
- Sulfur trioxide (SO3)

**Hint:** Create a list of the main chemical components of Portland cement to visualize its composition.

### Step 3: Determine the concentration of each component
From the information provided, we can summarize the approximate concentrations of these components in Portland cement:
- Silica (SiO2): 21.06%
- Calcium oxide (CaO): 57.98%
- Alumina (Al2O3): Not specified but is less than the major components.
- Iron oxide (Fe2O3): 3.08%
- Magnesium oxide (MgO): 2.74%
- Sulfur trioxide (SO3): 2.40%

**Hint:** Compare the percentages of each component to identify which one has the highest concentration.

### Step 4: Identify the major constituent
Among the listed components, calcium oxide (CaO) has the highest concentration at 57.98%. However, if the question is asking for a specific option among silica, alumina, iron oxide, and magnesium oxide, then silica (SiO2) has the highest percentage among these options.

**Hint:** Pay attention to the specific wording of the question to determine if it asks for the overall major constituent or one from a limited set of options.

### Conclusion
The major constituent of Portland cement, considering the options provided, is silica (SiO2).

**Final Answer:** Silica (SiO2) is the major constituent of Portland cement.