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RISHIKA JANA
2020-02-05
9.Water is an unusual compound whose physical properties set it
apart from other liquids.
Consider the following statements:
A.Water has a low dielectric constant.Water is therefore a non-
polar solvent,with the consequence that electrically charged
molecules or particles are easily separated in its presence.
B.Water has a very high heat capacity;a large amount of heat is
needed to raise its temperature each degree K.In biological
systems,this is an advantage,acting as a thermal buffer that
prevents the temperature of a cell:undergoing.moderate
metabolic activity from rising significantly.
C.Water has a low heat of vaporization unlike other liquids
capable of hydrogen bonding,such as ethanol and acetic acid.
D.Liquid water has a higher density than ice at standard
temperature and pressure.There is a negative volume change
upon freezing,which is why ice floats.
E.Water has a high surface tension.This requires biological
organisms to use detergent-like compounds to modify the surface
tension.Lung surfactants are an example of these detergents.
F.Water has a higher conductivity than might be expected on the
basis of its ionization constant alone.The conductivity of ice is
also high even though its ionization constant is 1000-fold lower.
This has been attributed to the presence of an ordered structure
which allows the electric charge to be carried by a modified
"brigade"mechanism.
Which of the following statement is NOT correct?
(1)D,E and F
(2)A, B and C
(3)A,C and D
(4)B,E and F