Question
Which one of the following is NOT present in cement?
NDA
General Ability
General Science
2025
NDA 2025 (Phase 2)
NDA General Ability Question (2025) — Solution
Options
- A. 2CaO SiO_2
- B. 3CaO SiO_2
- C. 4CaO SiO_2
- D. 3CaO Al_2O_3
Answer
C. 4CaO SiO_2
Step-by-step solution
Portland cement is a complex mixture of silicates and aluminates of calcium. The main constituents of Portland cement are: Dicalcium silicate (2CaO SiO_2) Tricalcium silicate (3CaO SiO_2) Tricalcium aluminate (3CaO Al_2O_3) Tetracalcium aluminoferrite (4CaO Al_2O_3 Fe_2O_3) Tetracalcium silicate (4CaO SiO_2) is not a constituent of cement. Answer: 4CaO SiO_2
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