Consider the following statements:
Statement I:
Studies indicate that carbon dioxide emissions from cement industry account for more than 5% of global carbon emissions.
Statement II:
Silica-bearing clay is mixed with limestone while manufacturing cement.
Statement III:
Limestone is converted into lime during clinker production for cement manufacturing.
Which one of the following is correct in respect of the above statements?
Let’s analyze each statement carefully: Statement I: Studies indicate that carbon dioxide emissions from the cement industry account for more than 5% of global carbon emissions. Correct The cement industry is a significant contributor to CO₂ emissions, around 5-7% of global emissions according to many studies. Statement II: Silica-bearing clay is mixed with limestone while manufacturing cement. Correct Cement raw mix typically contains limestone (source of calcium) and silica-bearing materials like clay or shale. The combination provides necessary oxides for clinker formation. Statement III: Limestone is converted into lime during clinker production for cement manufacturing. Correct In the kiln, limestone (CaCO₃) decomposes into lime (CaO) and CO₂ (this is called calcination). This step is a major source of CO₂ emissions in cement manufacturing. Explanation regarding Statement I: Statement III directly explains CO₂ emissions because the decomposition of limestone releases CO₂. Statement II relates to the raw materials but does not directly explain CO₂ emissions. Final Answer: (b) Both Statement II and Statement III are correct but only one of them explains Statement I