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WBCS Preliminary Examination 2019 — General Studies · Question 115 of 200

Q115
General ScienceChemistry
Which one among the following is the main ingredient in cement?
  1. a.Gypsum
  2. b.Limestone
  3. c.Clay
  4. d.Ash

Answer: (B) Limestone

Limestone (calcium carbonate) is the principal raw material in cement manufacturing, providing the calcium oxide that reacts with clay-derived silica and alumina during clinker formation; gypsum is added only in small amounts afterward to control the setting time.