Which member of each pair produces the more acidic aqueous solution: (a) ZnBr 2 or CdCl 2 (b) CuCl or Cu(NO 3 ) 2 (c) Ca(NO 3 ) 2 or NiBr 2

Well everyone. So in this video we're gonna go ahead and compare two different compounds and see which will give a more acidic aqueous solution when dissolved in water. So we have our iron to nitrates and we have our bromide. So we have to go ahead and remind ourselves again what the lewis acids and lewis bases are so far lewis acids, that's going to be our electron pair of sectors. And of course that just makes our lewis base our electron pair donors. Alright, now, comparing lewis acids, the metal with a higher positive charge will be the one that's more acidic. So because we are looking for a compound that will give us a more acidic solution when dissolved in water, we have to go ahead and write out that chemical equation. So first let's do iron to nitrates. So again, that's just F E N 02. Alright. And what that would give us is when it's after water our F E two plus KD on. And of course two moles of R N 02 minus an eye on. And we have the two coefficient in front of the ion to go ahead and balance this chemical equation out. All right, next one is going to be our fair bro. Mind again, that is just the F E B R three. So when dissolved in water, go ahead and turn into the F E three plus cat ion And of course three moles of our bromide ion. Okay, like I said again, we are comparing our medals, in this case. These are not our medals. It's always going to be our cannons. So we're working with r f E two plus versus r f E three plus and just looking at these positive charges and see which one has a higher positive charge. So two or three, it's going to be our three. R f E three plus is going to be definitely more acidic. Therefore then our answer is going to be like this. The question right here is going to be our more acidic one. So we can say that our f e B three plus r f e b R three, our favorite bromine is going to be more acidic and this right here is going to be my final answer.

Ch.16 - Acid-Base Equilibria

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Brown 14th Edition

Ch.16 - Acid-Base Equilibria

Problem 98

Chapter 16, Problem 98

Which member of each pair produces the more acidic aqueous solution: (a) ZnBr₂ or CdCl₂ (b) CuCl or Cu(NO₃)₂ (c) Ca(NO₃)₂ or NiBr₂

Verified step by step guidance

Identify the cation and anion in each compound: CuCl contains Cu^+ and Cl^-, while Cu(NO_3)_2 contains Cu^2+ and NO_3^-.

Consider the hydrolysis of the cations: Cu^+ is less likely to hydrolyze compared to Cu^2+, which can hydrolyze to form H^+ ions, increasing acidity.

Evaluate the anions: Cl^- is a weak conjugate base of a strong acid (HCl) and does not affect acidity, while NO_3^- is also a weak conjugate base of a strong acid (HNO_3) and does not affect acidity.

Compare the hydrolysis of the cations: Since Cu^2+ can hydrolyze to produce H^+ ions, Cu(NO_3)_2 is expected to produce a more acidic solution than CuCl.

Conclude that Cu(NO_3)_2 produces a more acidic aqueous solution than CuCl due to the hydrolysis of Cu^2+.

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Key Concepts

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

Acidity and pH

Acidity refers to the concentration of hydrogen ions (H+) in a solution, which determines its pH level. A lower pH indicates a more acidic solution. Understanding how different substances dissociate in water to release H+ ions is crucial for comparing their acidity.

Metal Cation Behavior

Metal cations can influence the acidity of a solution based on their charge and size. Cations like Cu²⁺ can hydrolyze in water, forming acidic solutions by releasing H+ ions. The extent of this hydrolysis is key to determining which compound is more acidic.

Complex Ion Formation

Complex ions form when metal cations coordinate with ligands, affecting their properties, including acidity. For example, Cu(NO3)2 may form complex ions that can alter the pH of the solution compared to simpler salts like CuCl. Understanding these interactions is essential for predicting acidity.