(c) rettile
         (d) haematite
Ans: (b)
90. Galena is an ore of the metal:
         (a) silver
         (b) lead
         (c) mercury
         (d) aluminium
Ans: (b)
91. Monozite is an ore of : [IAS (Pre) 1994]
         (a) Zarconium
         (b) Thorium
         (c) Titenium
         (d) Iron
Ans: (b)
92. The chemical formula of washing soda is : [BPSC 1999]
         (a) NaOH
         (b) Ca(OH)2
         (c) NaOHCO3
         (d) Na2CO310H2O
Ans: (d)
93. The metal which is more reactive than hydrogen is- [NDA 2010]
         (a) mercury
         (b) copper
         (c) silver
         (d) tin
Ans: (d)
94. The number of neutrons in 13Al27are: [NDA 2010]
         (a) 40
         (b) 27
         (c) 14
         (d) 13
Ans: (c)
95. In the earth crust although the amount of aluminium is found to be more than iron, however aluminium is costly
         than iron; because [NDA 1997]
         (a) aluminium is more useful than iron
         (b) aluminium forms more alloys than iron
         (c) aluminium made equipment are more acceptable then iron equipment
         (d) the extraction processes of aluminium are more costly than extraction processes of iron
Ans: (d)
96. Which one of the following is not a periodic property (does not show any trend) on moving from one side to
         another in the periodic table? [CDS 2010]
         (a) Atomic size
         (b) Valency
         (c) Radioactivity
         (d) Electronegativity
Ans: (c)
97. Which one of the following statement is true regarding the aluminium: [CDS 2002]
         (a) aluminium hydroxide is amphoteric in nature
         (b) aluminium exists in the free state in nature
         (c) nitric acid does not react with aluminium
         (d) hot and conc. H2SO4 directly reacts with oxygen in which SO2 gas is released
Ans: (b)
98. The chemical formula of plaster of peris is : [BPSC(Pre)1998]
         (a) CaSO4. 5H2O
         (b) 2CaSO4. H2O
         (c) (CaSO4)2. 2H2O
         (d) CaSO4.MgO
Ans: (b)
99. The chemical name of lime stone is: [UPPCS 1993]
         (a) Calcium chloride