Answer:
B. Wall applies equal reaction force on hand
Explanation:
This is newton's third law. You push something, that something pushes you back with same force. The direction is opposite, so if I push a wall, the wall pushes me back with same force just in opposite direction (so wall towards me). This is why option A is incorrect b/c it says force in same direction as wall. C and D talk about unequal force which is incorrect.
Explanation:
Relation between pressure, latent heat of fusion, and change in volume is as follows.

Also, 
where,
is the difference in specific volumes.
Hence, 
As,
= 22.0 J/mol K
And,
...... (1)
where,
= density of water
= density of ice
M = molar mass of water =
Therefore, using formula in equation (1) we will calculate the volume of fusion as follows.
=
=
Therefore, calculate the required pressure as follows.

=
or, = 145 bar/K
Hence, for change of 1 degree pressure the decrease is 145 bar and for 4.7 degree change dP =
= 681.5 bar
Thus, we can conclude that pressure should be increased by 681.5 bar to cause 4.7 degree change in melting point.
Answer:
Salt is the pure substance out of them all.