Which of the following pairs of substances would you expect to fo...

Question

Which of the following pairs of substances would you expect to form solutions?

a. CCl₄ and water
b. Benzene (C₆H₆) and MgSO₄
c. Hexane (C₆H₁₄) and heptane (C₇H₁₆)
d. Ethyl alcohol (C₂H₅OH) and heptanol (C₇H₁₅OH)

Accepted Answer

Welcome back. Everyone identify the pairs that will form solutions. For pair one, we have Cobalt two chloride and water. For pair two, we have octane and water. And for pair three, we have Taine and carbon tetrachloride. We have choice A which states that pair one Cobalt two chloride and water along with pair two octane and water will both form solutions. Choice B states that pair one Cobalt two chloride and water and pair three tone and carbon tetrachloride will both form solutions. Pair or option C says that pair two octane and water and pair three tone and carbon tetrachloride will both form solutions. And choice D states that all three pairs being pair one Cobalt two chloride and water. Pair two octane and water. And pair three toe and carbon tetrachloride will all form solutions. So let's begin by recalling our concept of solubility where we should recall that like dissolves like and so by like dissolves like we're referring to our solute and our solvent which should have like intermolecular forces or we can say similar intermolecular forces of either attraction or polarity in solution. So looking at pair one Cobalt two chloride and water we want to analyze each of our molecules. So Cobalt two chloride, we should recognize, we should recognize that this is an ionic compound. And between the electron negativity of chlorine and the electron negativity of Cobalt, we would associate chlorine as having a much greater electron negativity than Cobalt. And due to this very large difference in electron negativity represented as delta E N, We would therefore consider this to be polar cobalt two chloride is a polar solute. And next, we want to consider water h2o in which we would observe that between the electron negativity of oxygen and the electron negativity of hydrogen, we would see that oxygen has a much greater electron negativity than hydrogen. And so therefore, there is a large difference in electron negativity delta E N and therefore water is also polar. And because we have two polar substances, we would therefore have similar Intermolecular forces present, which we would identify the force present being ion dipole forces between Cobalt two chloride and water. And so therefore, this will form a solution Pair, one will form a solution. Now, looking at pair two, which considers octane C A H 18 and water. Beginning with octane, we want to recall that the electron negativity difference between carbon and hydrogen would be small. And therefore this molecule octane is nonpolar. This is also due to the fact that octane is a hydrocarbon just consisting of carbon and hydrogen in its chemical formula and recall that all hydrocarbons are nonpolar as we stated before, water is polar. And so as far as intermolecular force is present, water will definitely have its ion dipole intermolecular force as well as hydrogen bonding. However, octane is only going to have London dispersion forces. And so we do not have similar intermolecular forces present between this pair. And therefore, this will not form a solution. So we'll say will not form solution. So let's move, rule out any of our answer choices that do not include pair one, which would be choice C we can rule out as well as any answer choice that includes pair two, which would be choices A and D. So it looks like B would be the most correct choice so far. But let's verify this by looking at pair three, which considers to represented by the formula C six H five C H three and carbon tetrachloride CCL four. Now, for Owen, we can see that its chemical formula consists of just carbon and hydrogen and therefore, it's considered a hydrocarbon. And because it's a hydrocarbon, it's going to have a small difference in electron negativity between its atoms and therefore is a nonpolar substance. Whereas carbon tetrachloride we should recognize is asymmetrical structure. And so our dipoles will cancel between carbon and chlorine. And therefore, this means that carbon tetrachloride is nonpolar. So between our toluene and carbon tetrachloride, we have similar intermolecular forces present being our London dispersion forces. And this therefore means that we do have a solution formed between Halloween and carbon tetrachloride. So we can verify that pair one being Cobalt two chloride and water along with pair three being toe and carbon tetrachloride will be the only pairs that form solutions. So B one and three is our final answer. I hope this made sense and let us know if you have any questions.

Which of the following pairs of substances would you expect to form solutions? a. CCl₄ and water b. Benzene (C₆H₆) and MgSO₄ c. Hexane (C₆H₁₄) and heptane (C₇H₁₆) d. Ethyl alcohol (C₂H₅OH) and heptanol (C₇H₁₅OH)

Key Concepts

Polarity

Solubility

Hydrogen Bonding

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