In which of these solutions will HNO 2 ionize less than it does in pure water? a. 0.10 M NaCl b. 0.10 M KNO 3 c. 0.10 M NaOH d. 0.10 M NaNO 2

Hey, everyone. And welcome back to another video. In which of these solutions will nitrous acid ionize less than it does in pure water. We're given four answer choices. A 0.7 molar of sodium chloride, B 0.7 molar of potassium nitrate. C 0.7 molar of sodium hydroxide and D 0.7 molar of sodium nitrate. First of all, let's write down the ionization equation. So we have HNO two that's nitrous acid. In order for it to ionize, it must react with water. And therefore, we have a proton transfer. We have an equilibrium reaction where we are producing H 30 plus which is hydro and nitrite, right. No two minus. If we want to ionize it less than it does in pure water. This means that according to the principle of Lucia, we want to shift the equilibrium to the left towards the formation of the reactants instead of products. And we can do that by utilizing the common iron effect, which essentially allows us to do so. If we initially have at least one of the ions on the right hand side, then we are able to shift the equilibrium to the left. So looking at the substances that we have starting with a sodium chloride associates in a solution into sodium cations and chloride anions. And none of these ions corresponds to the iron on the right hand side. Right. So it has no effect, we can essentially neglect the ionic strength and say that roughly there would be no effect to the degree of ionization. Now, b we have pedestrian nitrate which dissociates into potassium cation ions and nitrate nitrate anions. And once again, none of them correspond to the ions on the right. C sodium hydroxide associates the sodium CS and hydroxide anions. And actually hydroxide would react with hydro to produce water. So it would essentially neutralize the acid and it would drive the reaction forward instead of in a reverse direction, right. So it's the opposite effect that would actually increase the degree of ionization by essentially removing hydro from the solution. And D should be the right answer, right? Because this is our final option. We have once again, sodium ions and nitrite anions, which indeed tells us that we now have a common ion. Now, essentially this means that initially, if we add sodium nitrate, it would allow us to shift the equilibrium to the left and not allow for H 102 to ionize that much due to the initial amount of nitride. Therefore, we can conclude that the correct answer to this problem would be option D zero point, some molar of sodium nitrate is the substance. Or actually, in this case, the solution that would make nitrous acid ionized less than it does in pure water due to the common iron effect. Thank you for watching.

Ch.18 - Aqueous Ionic Equilibrium

All textbooks

Tro 6th Edition

Ch.18 - Aqueous Ionic Equilibrium

Problem 27

Chapter 18, Problem 27

In which of these solutions will HNO₂ ionize less than it does in pure water? a. 0.10 M NaCl b. 0.10 M KNO₃ c. 0.10 M NaOH d. 0.10 M NaNO₂

Verified step by step guidance

Identify the common ion effect, which states that the ionization of a weak acid or base is suppressed in the presence of a common ion from another source.

Examine each option to determine if it contains a common ion with HNO2. HNO2 is a weak acid that partially dissociates into H+ and NO2- ions in solution.

Recognize that NaCl dissociates into Na+ and Cl- ions, neither of which is a common ion with HNO2, so it does not affect the ionization of HNO2.

Note that KNO3 dissociates into K+ and NO3- ions. Since NO3- is not the same as NO2-, it does not provide a common ion to HNO2, thus not affecting its ionization.

Identify that NaNO2 dissociates into Na+ and NO2- ions. The NO2- ion is a common ion with HNO2, which will suppress the ionization of HNO2 due to the common ion effect.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Was this helpful?

Key Concepts

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

Ionization of Weak Acids

Weak acids, like HNO2 (nitrous acid), do not fully ionize in solution. The degree of ionization depends on the concentration of the acid and the presence of other ions in the solution. In pure water, HNO2 will ionize to a certain extent, but this ionization can be affected by the addition of other solutes.

Common Ion Effect

The common ion effect occurs when a salt containing an ion that is also produced by the weak acid is added to the solution. This increases the concentration of that ion, shifting the equilibrium of the weak acid's ionization reaction to the left, thereby reducing the degree of ionization. For example, adding NaNO2 introduces NO2- ions, which will suppress the ionization of HNO2.

Colligative Properties

Colligative properties depend on the number of solute particles in a solution rather than their identity. When a non-volatile solute like NaCl or KNO3 is added to water, it can affect the physical properties of the solution, such as vapor pressure and boiling point. However, in the context of weak acid ionization, the presence of ions from strong electrolytes can influence the ionization behavior of weak acids.