Multiple Choice QuestionsWhich of the following methods is used for the removal of temporary hardness of water?
Treatment with washing soda
Calgon method
lon-exchange method
Clark's method
Temporary hardness of water is removed in Clark's process by adding
caustic soda
calgon
borax
lime
D.
lime
The temporary hardness of water is due to the presence of bicarbonates of Ca and Mg. This may be removed by Clark's process. In this process, addition of calculated quantity of lime causes precipitation of CaCO3 as
Ca(HCO3)2 + Ca(OH)2 → 2CaCO3↓ +2H2O
and Mg(HCO3)2 + 2Ca(OH)2 → 2CaCO3↓ + Mg(OH)2 + 2H2O
On which of the following principles hydrogen bomb is based?
Nuclear fission
Nuclear fusion
Artificial radioactivity
Natural radioactivity
The IE of hydrogen atom is 13.6 eV. The energy required to remove an electron in the n = 2 state of the hydrogen atom is
27.2 eV
13.6 eV
6.8 eV
3.4 eV
Hydrogen is prepared on large scale for industrial use
by Zn + H2SO4
by Al + NaOH
by Na + C2H5OH
from water gas
When conc. H2SO4 comes in contact with sugar, it becomes black due to
hydrolysis
hydration
decolourisation
dehydration
The temperature of maximum density of H2O and D2O respectively are
0°C and 11.6°C
4°C and 0°C
4°C and 11.6°C
4°C and 12.5°C
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