Answer:
The answer to your question is: The first option is correct.
Explanation:
From the data given, we conclude that as the amount of salt increases, the boiling point of water increases.
Options
If salt is added to water, the water will boil at a higher temperature This is the hypothesis for the experiment.
Salt makes water boil. This statement is not true.
If water is boiling, it must have salt added to it. This statement is incorrect, it is not the goal of the experiment.
If salt is added to water, the water will get cloudy There is not evidence of that from the information given.
Answer : The number of moles of
produced will be, 0.241 moles.
Solution : Given,
Mass of Fe = 27.0 g
Molar mass of
= 56 g/mole
First we have to calculate the moles of
.

Now we have to calculate the moles of 
The balanced chemical reaction is,

From the reaction, we conclude that
As, 4 mole of
react to give 2 mole of 
So, 0.482 moles of
react to give
moles of 
Thus, the number of moles of
produced will be, 0.241 moles.
Answer : The
for this reaction is, -88780 J/mole.
Solution :
The balanced cell reaction will be,

Here, magnesium (Cu) undergoes oxidation by loss of electrons, thus act as anode. silver (Ag) undergoes reduction by gain of electrons and thus act as cathode.
The half oxidation-reduction reaction will be :
Oxidation : 
Reduction : 
Now we have to calculate the Gibbs free energy.
Formula used :

where,
= Gibbs free energy = ?
n = number of electrons to balance the reaction = 2
F = Faraday constant = 96500 C/mole
= standard e.m.f of cell = 0.46 V
Now put all the given values in this formula, we get the Gibbs free energy.

Therefore, the
for this reaction is, -88780 J/mole.
The second one, I could be mistaken though