Answer : The concentration of Si in kilograms is, 
Explanation :
As we are given that, the concentration of Si in an Fe-Si alloy is 0.25 wt% that means:
Weight of Si = 0.25 g = 0.00025 kg
Weight of Fe = 100 - 0.25 = 99.75 g = 0.09975 kg
Density of Si = 
Density of Fe = 
Now we have to calculate the concentration in kilograms of Si per cubic meter of alloy.
Concentration of Si in kilograms = 
Concentration of Si in kilograms = 
Now put all the given values in this expression, we get:
Concentration of Si in kilograms = 
Concentration of Si in kilograms = 
Thus, the concentration of Si in kilograms is, 
<u>Answer:</u> The boiling point of solution is 
<u>Explanation:</u>
To calculate the elevation in boiling point, we use the equation:

Or,

where,

Boiling point of pure liquid = 118.90°C
i = Vant hoff factor = 2 (For potassium bromide)
= molal boiling point elevation constant = 0.82°C/m
= Given mass of solute (potassium bromide) = 54. g
= Molar mass of solute (potassium bromide) = 119 g/mol
= Mass of solvent (liquid X) = 750. g
Putting values in above equation, we get:

Hence, the boiling point of solution is 
If you weigh 1.00 mL of liquid water it will have a mass of about 1 g so its density is about 1 g/mL or 1 g mL-1.