Which molecule would you expect to be more soluble in water: CH 3 CH 2 CH 2 OH or HOCH 2 CH 2 CH 2 OH?

Welcome back everyone to another video. Which molecule would you expect to be more soluble in water? Ethanol or one comma three propane dial. And we are given for answer choices A states, ethanol B states A one comma three propane dial C states. Both of them have equal solubility and d neither of them dissolves in water. So first of all, let's understand that we are considering two alcohols, they both have that hydrocarbon chain within a wage group. So first of all, we can essentially state that if we expand it for the first molecule or ethanol, we have CG we C h2o H right? And the second one is also an alcohol which has 20 groups. So we have ohch two, we can essentially state that we have this three times, right? And after that, we can also state that we have another o age group. So now let's remember that alcohols, they are compounds that have carbon bonds to the wage group, right? We want to make sure that our carbon is saturated, meaning it has single bonds. So in general, whenever we have our wage, this is an alcohol, both of them are alcohols and I want to draw your attention that the wage group is actually of the greatest importance in this problem because those alcohol groups can actually form hydrogen bonds, right? This is really important. First of all, we want to consider the size of each molecule, the first molecule is smaller, we can see that the chain is shorter, right? So it's smaller, which is essentially important for solubility in water. We want to make sure that it's small. However, hygiene bonding is more important whenever we consider the solubility in water. Because if alcohols can form hydrogen bonds with water and the greater the number of bonds, we can form the the greater the solubility. Recall the rule like dissolve sl it means that polar compounds are soluble in polar solvents. And since water is polar, we want to identify which molecule is more polar. And the answer is the second one because it has a greater number of old age groups to a wage verses one. It's more polar, that's already sufficient for us to understand that it would be more soluble in water because water is also polar. However, in addition to that, those the age groups can form, can form more hydrogen bonds. And therefore, as a result, the second compound would be more soluble in water. We can essentially state that answer B is the correct option. One comma three propane dial is more soluble in water because it's more polar. It has a greater number of the alcohol groups. Thank you for watching.

Ch.14 - Solutions

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Tro 6th Edition

Ch.14 - Solutions

Problem 31

Chapter 14, Problem 31

Which molecule would you expect to be more soluble in water: CH₃CH₂CH₂OH or HOCH₂CH₂CH₂OH?

Verified step by step guidance

Identify the functional groups in each molecule. CH3CH2CH2OH has an alcohol group (-OH) attached to a propyl group, while HOCH2CH2CH2OH has an alcohol group at both ends of a propane chain.

Consider the polarity of the molecules. Molecules with higher polarity are generally more soluble in water, which is a polar solvent.

Assess the ability of the molecules to form hydrogen bonds with water. Hydrogen bonding significantly enhances solubility in water.

Compare the number of hydroxyl groups (-OH) in each molecule. More hydroxyl groups typically increase the hydrophilicity (water-loving nature) of the molecule.

Conclude which molecule is more likely to be soluble in water based on the presence of more hydroxyl groups and the overall polarity.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Polarity of Molecules

Polarity refers to the distribution of electrical charge over the atoms in a molecule. Polar molecules, which have a significant difference in electronegativity between their atoms, tend to interact favorably with water, a polar solvent. In contrast, nonpolar molecules do not dissolve well in polar solvents due to their lack of charge separation.

Hydrogen Bonding

Hydrogen bonding is a strong type of dipole-dipole interaction that occurs when hydrogen is bonded to highly electronegative atoms like oxygen or nitrogen. Molecules capable of forming hydrogen bonds with water can enhance their solubility. The presence of hydroxyl (-OH) groups in a molecule increases its ability to form hydrogen bonds with water.

Hydrophobic vs. Hydrophilic Interactions

Hydrophobic interactions occur between nonpolar molecules that repel water, while hydrophilic interactions involve polar or charged molecules that attract water. Molecules with long nonpolar hydrocarbon chains are typically hydrophobic, reducing their solubility in water. In contrast, molecules with more polar functional groups are hydrophilic and tend to dissolve better in aqueous environments.