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Compounds of calcium and magnesium
Concepts tested here
- Formulae of sulphate minerals
All Questions
2011 AIPMT-MAINS 1 question
-
Match List-I with List-II for the composition of substances and select the correct answer.
Pick the matching item from Column II for each row.
Column I
- A. Plaster of Paris
- B. Epsomite
- C. Kieserite
- D. Gypsum
Column II
- i. $CaSO_4\cdot2H_2O$
- ii. $CaSO_4\cdot\frac{1}{2}H_2O$
- iii. $MgSO_4\cdot7H_2O$
- iv. $MgSO_4\cdot H_2O$
- v. $CaSO_4$
Correct answer: A → ii, B → iii, C → iv, D → i
Plaster of Paris is the hemihydrate of calcium sulphate, $CaSO_4\cdot\frac{1}{2}H_2O$, obtained by heating gypsum at 393 K.
Epsomite (Epsom salt) is magnesium sulphate heptahydrate, $MgSO_4\cdot7H_2O$.
Kieserite is magnesium sulphate monohydrate, $MgSO_4\cdot H_2O$.
Gypsum is calcium sulphate dihydrate, $CaSO_4\cdot2H_2O$.
Anhydrous $CaSO_4$ ('dead burnt plaster') is not matched with any of the four substances.
Correct match: A-ii, B-iii, C-iv, D-i.
