Water could be made
to boil at 105 degrees Celsius instead of 100 degrees Celsius by taking
the sample to a higher altitude. Pressure is directly proportional to
temperature. So when you bring water into higher altitude, you are increasing
the external pressure and therefore increase the boiling point.
Answer:
(a) Homogeneous. 4.7 g of MgCl₂.
(b) 9.1 g
Explanation:
(a)
At 200°C, we can dissolve 54.6g of MgCl₂ in 100 g of water. The mass that we could dissolve in 38.2 g of water is:

Since we can dissolve up to 20.9 g of MgCl₂ and we added only 16.2 g, the mixture is homogeneous and we could add 20.9 g -16.2 g = 4.7 g of solute to make it saturated.
(b)
At 800°C, we can dissolve 66.1 g of MgCl₂ in 100 g of water. The mass that we could dissolve in 38.2 g of water is:

Since we can dissolve up to 25.3 g of MgCl₂ and we added only 16.2 g, we could add 25.3 g - 16.2 g = 9.1 g of solute to make it saturated.
Answer: The Answers are: 0.31g & 0.011mol & 3.34g & 0.016mol.
Explanation: Solved in the attached picture.