The coagulation values in millimoles per litre of the electrolytes used for the coagulation of As2S3 are given below :
I. (NaCl) = 52,
II. (BaCl2) = 0.69,
III. (MgSO4) = 0.22
The correct order of their coagulating power is
A
I > II > III
B
II > I > III
C
III > II > I
D
III > I > II
Explanation
As,
Coagulating power $$\infty $$
1
Coagulation value
Lower the coagulation value, higher is the
coagulating power so, the correct order is :
III > II > I
2
MCQ (Single Correct Answer)
NEET 2016 Phase 1
Which one of the following characteristics is associated with adsorption?
A
$$\Delta $$G and $$\Delta $$H are negative but $$\Delta $$S is positive.
B
$$\Delta $$G and $$\Delta $$S are negative but $$\Delta $$H is positive.
C
$$\Delta $$G is negative but $$\Delta $$H and $$\Delta $$S are positive.
D
$$\Delta $$G, $$\Delta $$H and $$\Delta $$S all are negative.
Explanation
Adsorption is spontaneous process,
therefore change in the free energy ( $$\Delta $$G) for the
process is negative.
As we know that
$$\Delta $$G = $$\Delta $$H – T$$\Delta $$S
S is negative because adhering of gas molecules
to the surface lowers the randomness.
$$ \therefore $$ $$\Delta $$G can be –ve only when $$\Delta $$H is –ve.
3
MCQ (Single Correct Answer)
AIPMT 2015 Cancelled Paper
Which property of colloidal solution is independent of charge on the colloidal particles?
A
Electro-osmosis
B
Tyndall effect
C
Coagulation
D
Electrophoresis
Explanation
Tyndall effect is the scattering of light by sol
particles which cannot be affected by charge on
them.
4
MCQ (Single Correct Answer)
AIPMT 2014
Which property of colloids is not dependent on the charge on colloidal particles?
A
Coagulation
B
Electrophoresis
C
Electro-osmosis
D
Tyndall effect
Explanation
Tyndall effect is due to the scattering of
light by colloidal particles and not due to the charge.
Questions Asked from Surface Chemistry
On those following papers in MCQ (Single Correct Answer) Number in Brackets after Paper Name Indicates No of Questions