Problem 44
Which of the following is calcium superphosphate? (a) \(\mathrm{Ca}\left(\mathrm{H}_{2} \mathrm{PO}_{4}\right)_{2} \mathrm{H}_{2} \mathrm{O}+\mathrm{CaSO}_{4}\) (b) \(\mathrm{CaSO}_{4}+\mathrm{CaO}\) (c) \(\mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}+2 \mathrm{CaSO}_{4}\) (d) \(\mathrm{Ca}\left(\mathrm{H}_{2} \mathrm{PO}_{4}\right)_{2} \mathrm{H}_{2} \mathrm{O}+2\left(\mathrm{CaSO}_{2}-2 \mathrm{H}_{2} \mathrm{O}\right)\)
Problem 45
What is the molecular formula of plaster of paris? (a) \(\mathrm{CaSO}_{4}, 2 \mathrm{H}_{2} \mathrm{O}\) (b) \(2 \mathrm{CaSO}_{4} \mathrm{H}_{2} \mathrm{O}\) (c) \(2 \mathrm{CaSO}_{4} 2 \mathrm{H}_{2} \mathrm{O}\) (d) \(\mathrm{CaSO}_{4} 3 \mathrm{H}_{2} \mathrm{O}\)
Problem 46
Mortar is a mixture of (a) slaked lime + silica \(+\mathrm{H}_{2} \mathrm{O}\) (b) \(\mathrm{CaCO}_{3}+\) silica \(+\mathrm{H}_{2} \mathrm{O}\) (c) slaked lime + plaster of paris \(+\mathrm{H}_{2} \mathrm{O}\) (d) plaster of paris + silica
Problem 47
Which of the following is an alloy of aluminium? (a) magnallium (b) duralumin (c) brass (d) both (a) and (b)
Problem 48
What is the molecular formula of gypsum? (a) \(\mathrm{CaSO}_{4} \cdot 2 \mathrm{H}_{2} \mathrm{O}\) (b) \(\mathrm{CaSO}_{4} \cdot 3 \mathrm{H}_{2} \mathrm{O}\) (c) \(\mathrm{CaSO}_{a} \mathrm{H}_{2} \dot{O}\) (d) \(2 \mathrm{CaSO}_{4} \mathrm{H}_{2} \mathrm{O}\)
Problem 49
In the Castner's process of extraction of sodium cathode is (a) nickel rod (b) iron rod (c) graphite rod (d) copper rod
Problem 50
Which of the following is incorrect? (a) \(\mathrm{Mg}\) bums in air releasing dazaling light rich in uv rays (b) \(\mathrm{CaCl}_{2} 6 \mathrm{H}_{2} \mathrm{O}\) when mixed with ice gives a freering mixture (c) \(\mathrm{Mg}\) cannot form complexes (d) Be can form complexes due to its very small sipe
Problem 51
An important ore of magnesium is (a) malachite (b) cassiterite (c) carnalite (d) galena
Problem 52
\(\mathrm{Mg}\) is an important component of which biomolecule occurring extensively in living world? (a) cholorophyll (b) haemoglobin (c) ATP (d) florigen
Problem 53
Plaster of paris is used (a) in dentistry and surgery (b) as a plaster for walls (c) as a drying agent (d) in metallurgical process
