i believe the answer is A (((:
Explanation:
The given data is as follows.
Weight of solute = 75.8 g, Molecular weight of solute (toulene) = 92.13 g/mol, volume = 200 ml
- Therefore, molarity of toulene is calculated as follows.
Molarity = 
= 
= 4.11 M
Hence, molarity of toulene is 4.11 M.
- As molality is the number of moles of solute present in kg of solvent.
So, we will calculate the molality of toulene as follows.
Molality = 
= 
= 8.6 m
Hence, molality of given toulene solution is 8.6 m.
- Now, calculate the number of moles of toulene as follows.
No. of moles = 
= 
= 0.8227 mol
Now, no. of moles of benzene will be as follows.
No. of moles = 
= 
= 1.2239 mol
Hence, the mole fraction of toulene is as follows.
Mole fraction = 
= 
= 0.402
Hence, mole fraction of toulene is 0.402.
- As density of given solution is 0.857
so, we will calculate the mass of solution as follows.
Density = 
0.857
=
(As 1
= 1 g)
mass = 171.4 g
Therefore, calculate the mass percent of toulene as follows.
Mass % = 
= 
= 44.22%
Therefore, mass percent of toulene is 44.22%.
The hydrogen deficiency index( HDI) of strigol is = 10
<h3>How to calculate HDI:</h3>
The hydrogen deficiency index is used to measure the number of degree of unsaturation of an organic compound.
Strigol is an example of an organic compound because it contains carbons and hydrogen.
To calculate the HDI using the molecular formula given (C19H20O6) the formula for HDI is used which is:

where C = number of carbon atoms = 19
n= number of nitrogen atoms = 0
h= number of hydrogen atoms = 20
X = number of halogen atoms = 0
Note that oxygen was not considered because it forms two bonds and has no impact.
There for HDI =

HDI=

HDI =

HDI = 10
Therefore, the hydrogen deficiency index of strigol is = 10
Learn more about unsaturated compounds here:
brainly.com/question/490531
Answer:
By adding the solute in to solution boiling point is increased while freezing point is decreased.
Explanation:
When solute in added into the solvent the boiling point of solvent increases for example,
Water is boiled at 100 °C, when sodium chloride is added its boiling point increased. Ions of salt interact with solvent and prevent the water molecules to escape from the surface and form gas molecules. In order to make it boiled solution must be heated above 100 °C.
But there is different case with freezing point. Freezing point is the state in which substance converted into the solid. At given temperature when solute is added into the solvent it prevent the formation of solid. It required time to decrease the temperature first and as the temperature is decreases solid is formed.