Which of the following in each pair is likely to be more soluble in water: (b) propionic acid (CH 3 CH 2 COOH) or sodium propionate (CH 3 CH 2 COONa)

welcome back everyone in this example, we have Dyke Lovren which is also known as die cyclamen, a drug used to cure gastrointestinal tract spasms. The conversion of the free based form of decluttering to the protein ated hydrochloride form using one equivalent of hydrochloric acid is shown below. Note that not all carbons and hydrogen are shown and that each corner represents a carbon atom bonded to the correct number of hydrogen in order to make a total of four bonds. So this carbon here would be bonded to two hydrogen atoms where it's also bonded to these two carbon atoms. For its total of four bonds stable or to keep the carbon atoms staple. Were asked based on the given structure, determine which form of dice take Lovering is more soluble in water. And we want to make note of the fact that water is a polar molecule. So we want to figure out which form of Dick Lovren has the strongest inter molecular forces for our first structure. We can easily see that we have dipole dipole forces where we have for example, the nitrogen atom here compared to its bonds to carbon in the structure because we recognize that nitrogen is more electro negative than carbon based on our electro negativity trend, which we should recall increases as we go towards the top right of our periodic table towards flooring. Therefore nitrogen because it's more electro negative will have a slightly negative charge and our carbon atoms will have a slightly positive charge, creating this dipole dipole force as our inter molecular forces in our Dick Lovering. Now moving on to our decluttering hydrochloride. We can see that we have an ion specifically a caddy on charge on this nitrogen atom here. And we should recall that decluttering hydrochloride is actually a salt because it's considered an ionic compound which explains that positive charge on the nitrogen there. So because it's considered assault, we possibly have ion dipole interaction which is a very strong inter molecular force stronger than dipole dipole. We also should recognize that we have a hydrogen atom in our structure, meaning we have hydrogen bonding as our second inter molecular force. So we have h bonding And recall that hydrogen bonding is also one of the stronger inter molecular forces. And then of course on top of all of this we definitely have our dipole dipole forces. And because we have these three total very strong inter molecular forces associated with our dike Lovering hydrochloride, we're going to confirm that it will have a even greater polarity than dike Lovering and so it's going to be more soluble in water. So our final answer is going to be that the dike Lovering hydrochloride is going to be more soluble in water due to its presence of these three outlined inter molecular forces. I hope everything I explained was clear what's highlighted in yellow is our final answer. If you have any questions leave them down below and I'll see everyone in the next practice video

Ch.13 - Properties of Solutions

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Brown 15th Edition

Ch.13 - Properties of Solutions

Problem 34b

Chapter 13, Problem 34b

Which of the following in each pair is likely to be more soluble in water: (b) propionic acid (CH₃CH₂COOH) or sodium propionate (CH₃CH₂COONa)

Verified step by step guidance

Identify the nature of each compound: Propionic acid (CH3CH2COOH) is a carboxylic acid, while sodium propionate (CH3CH2COONa) is a salt formed from the neutralization of propionic acid with sodium hydroxide.

Consider the solubility rules: Generally, salts of sodium (Na+) are highly soluble in water due to the strong ionic interactions between the ions and water molecules.

Analyze the molecular interactions: Propionic acid can form hydrogen bonds with water due to its -COOH group, but it is a weaker acid and less ionized in water compared to its sodium salt.

Compare the solubility: Sodium propionate, being an ionic compound, will dissociate completely in water, increasing its solubility compared to the molecular form of propionic acid.

Conclude based on solubility principles: Sodium propionate is likely to be more soluble in water than propionic acid due to its ionic nature and the presence of the highly soluble sodium ion.

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Key Concepts

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

Polarity and Solubility

The principle of 'like dissolves like' states that polar substances tend to dissolve in polar solvents, while nonpolar substances dissolve in nonpolar solvents. Water is a polar solvent, meaning that ionic and polar compounds are generally more soluble in it. Understanding the polarity of the molecules in question is crucial for predicting their solubility.

Ionic Compounds in Water

Ionic compounds, such as sodium propionate, dissociate into their constituent ions when dissolved in water. This dissociation increases the interaction with water molecules, enhancing solubility. In contrast, molecular compounds like propionic acid may not dissociate as completely, affecting their overall solubility in water.

Hydrogen Bonding

Hydrogen bonding occurs when hydrogen is covalently bonded to a highly electronegative atom, such as oxygen, creating a polar molecule. Both propionic acid and sodium propionate can form hydrogen bonds with water, but the presence of the ionic sodium ion in sodium propionate enhances its solubility due to stronger interactions with water compared to the neutral propionic acid.