Potash alum is used in purification of water because:

1. it kills the micro-organisms

2. it precipitates the colloidal matter

3. it removes the hardness of water

4. it catalyses the removal of impurities

The pair of compounds which cannot exist together in solution is:

1. NaHCO₃ and NaOH

2. Na₂CO₃ and NaHCO₃

3. Na₂CO₃ and NaOH

4. NaHCO₃ and NaCl

Which one is the highest melting point halide?

1. NaCl

2. NaBr

3. NaF

4. NaI

LiAlH₄ is obtained by reacting an excess of ...... with an etheral solution of AlCl₃.

1. LiCl

2. LiH

3. Li

4. LiOH

Manufacture of NaOH is done by:

1. Castner - Kellner process

2. Solvay process

3. Brine process

4. Mond's process

Sodium does not form Na²⁺ ,because:

1. Sodium contains only one electron in its outermost shell

2. First ionization potential is small and the difference in first and second ionization potential is very large.

3. Radius of Na⁺² is much smaller than of Na⁺

4. None of the above.

Lithium is the only alkali metal which is not placed in kerosene but is wrapped in paraffin wax, because:

1. it reacts with kerosene

2. it floats to the surface of kerosene because of low density

3. it does not react with air and H₂O

4. none of the above

When CO₂ is bubbled into an aqueous solution of Na₂CO₃, the following is formed:

1. H₂O

2. OH-

3. NaHCO₃

4. NaOH

The element which does not dissolve in caustic soda is:

1. silicon

2. aluminium

3. zinc

4. cadmium

The principal products obtained on heating iodine with concentrated caustic soda solution are:

1. NaOI + NaI

2. NaIO₃ + Nal

3. NaOI + NaIO₃ + NaI

4. NaIO₄ + NaI