1.a. Which of the following would you expect to be soluble in hexane (C 6 H 14 ,

Question

1.a. Which of the following would you expect to be soluble in hexane (C6H14, pick all that apply)?

I2                     KI                    Br2                   NaBr

b.For those above that you would expect to be soluble in hexane, what intermolecular force is present between solvent and solute?

c.What is the strongest intermolecular force between solvent and solute in each case below?

I2 dissolved in water                KI dissolved in water Methanol (CH3OH) dissolved in water.

d.50.00 mL of a KCl solution was heated until all of the water evaporated. The solution had a mass of 50.552 g, and the mass of the salt left behind after evaporation was 46.332 g. What is the molarity of the KCl solution?

Explanation / Answer

Ans 1 a.

Like dissolves Like .

Since hexane is non polar molecule , so it will dissolve all non polar compounds .

So the compounds soluble in hexane are I2 and Br2 , as they are non polar , rest KI and NaBr are ionic hence they dissolve in polar compounds such as water .

b)

London dispersion forces or Vander waal forces are present in between the halogen ( I2 , Br2) molecules and hexane .

c)

Iodine does not dissolve in water.

KI has ion - dipole forces present in between the molecules of itself and water molecules .

Methanol will have intermolecular dipole interactions and hydrogen bonding between its molecules and water molecules.

Hence the strongest intermolecular force will be in the case of methanol in water .

d)

Mass of salt = 50.552 - 46.332 = 4.22 g

No. of moles of KCl = 4.22 / 74.5513 = 0.057 moles

Molarity = no. of moles / volume of solution in Litre

= 0.057 / 0.050

= 1.13 M

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