Question

Which of the following formulae is mismatched?

• A. Green vitriol $- FeSO_4 \cdot 7H_2O$
• B. Potash alum $- K_2SO_4.Al_2(SO_4)_3 \cdot 24H_2O$
• C. Plaster of Paris $- CaSO_4 \cdot 2H_2O$
• D. Epsom salt $- MgSO_4 \cdot 7H_2O$

Answer 1

Answer: (C)

Plaster of Paris $- CaSO_4 \cdot 2H_2O$

Answer 2

Plaster of Paris is $CaSO_{4} \frac{1}{2}H_{2}O$