Rank the following compounds according to increasing water solubility: i) CH 3 -CH 2 -CH 2 -CH 3 ii) CH 3 -CH 2 -O-CH 2 -CH 3 iii) CH 3 -CH 2 -OH iv) CH 3 -OH

So this practice problem wants us to rank the following compounds according to increasing water solubility. And so we have the roman numerals here indicating the compounds and the letters here indicate our answer options which rank the compounds based on their solubility. And so I can tell you here that one of the above is the correct answer, so let's go ahead and cross off e. Now, recall from our previous videos that water solubility will be highest when there are more polar groups and less nonpolar groups. So when we look at compound number 1 and compare it to the other compounds, what we'll notice is that it has 0 polar groups. They're all carbon hydrogen bonds which are all non polar, which whereas the other compounds have these oxygen atoms in it which create these polar groups. And so because this one has 0 polar groups, this has to have the lowest solubility. So we'll put compound number 1 or Roman numeral I here for this compound as the lowest solubility. Now when we look at compound 2 and compare it to the others, the polar group is embedded in between 2 nonpolar groups. So the CH twos and CH threes are nonpolar, and it's harder for water to get in and interact with this oxygen here if, there's all of these non polar groups that are surrounding it. And so the other polar groups on the other two molecules are on the end of the molecule which makes it easier for water to interact. And so, because of that, roman numeral number 2 compound is gonna be next in line for solubility. Now, when we compare, compound 3 to compound 4, they both have the polar group on the end. And the only difference is that compound 3 has this additional c h two group, which is a nonpolar group. So it has more nonpolar groups than compound 4, so that makes it, less soluble. So compound 3 is gonna be next and then the the highest solubility is gonna be compound 4. So the only answer option that has these compounds ranked in this order from low solubility to high solubility is gonna be answer option d. So we can go ahead and cross off the other answer options, indicate that d is the correct option, and I'll see you guys in our next video.

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1. Introduction to Biochemistry4h 34m
2. Water3h 23m
3. Amino Acids8h 10m
4. Protein Structure10h 4m
5. Protein Techniques14h 5m
6. Enzymes and Enzyme Kinetics13h 38m
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12. Biosignaling9h 45m
Review 1: Nucleic Acids, Lipids, & Membranes2h 47m
Review 2: Biosignaling, Glycolysis, Gluconeogenesis, & PP-Pathway3h 12m
Review 3: Pyruvate & Fatty Acid Oxidation, Citric Acid Cycle, & Glycogen Metabolism2h 26m
Review 4: Amino Acid Oxidation, Oxidative Phosphorylation, & Photophosphorylation1h 48m

2. Water

Properties of Water

Biochemistry

2. Water

Properties of Water

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Multiple Choice

Rank the following compounds according to increasing water solubility:
i) CH₃-CH₂-CH₂-CH₃
ii) CH₃-CH₂-O-CH₂-CH₃
iii) CH₃-CH₂-OH
iv) CH₃-OH

i < iii < iv < ii

i < ii < iv < iii

iii < iv < ii < i

i < ii < iii < iv

None of the above are correct.

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Understand that water solubility is influenced by the presence of polar groups and hydrogen bonding capabilities in a molecule.

Identify the functional groups in each compound: i) CH3-CH2-CH2-CH3 is an alkane, ii) CH3-CH2-O-CH2-CH3 is an ether, iii) CH3-CH2-OH is an alcohol, and iv) CH3-OH is also an alcohol.

Recognize that alcohols generally have higher solubility in water due to their ability to form hydrogen bonds with water molecules, compared to ethers and alkanes.

Compare the alcohols: CH3-OH (methanol) has a smaller hydrophobic region compared to CH3-CH2-OH (ethanol), making methanol more soluble in water.

Rank the compounds based on the presence of polar groups and hydrogen bonding: i) CH3-CH2-CH2-CH3 (least soluble, no polar groups), ii) CH3-CH2-O-CH2-CH3 (ether, limited hydrogen bonding), iii) CH3-CH2-OH (ethanol, more hydrogen bonding), iv) CH3-OH (methanol, most hydrogen bonding).