when dissolved in an aqeous solution, which of the following salts will yield an acidic solution? NH4Cl, NaClO4, Na2S, MgBr2, Ba(CH3CO2)2
You look at the hydrolysis of each salt. For example, NH4Cl.
The Cl^- is a weak base and will not pull H^+ away from water; therefore, Cl^- is not hydrolyzed. The NH4^+ will donate a H^+ to water forming.
NH4^+ H2O ==> NH3 + H3O^+, thus, this is an acidic solution.
All of the texts and most teachers use this approach and if you are familiar with the acidity and/or basicity of catins and anions, this works quite well. However, WAY BACK when I was a student, we didn't use the Bronsted-Lowry theory that much so we had another way to do it. Your teacher won't like this, probably, but it works.
I write the molecular equation, for example, for NH4Cl.
NH4Cl + HOH ==> NH4OH + H^+
NH4OH (which has now been shown not to exist but it is NH3 + H2O) is a weak base, HCl is a strong acid, strong wins out over weak, so the salt is acidic in aqueous solution.
Another one.
NaClO4 + HOH ==> NaOH + HClO4.
NaOH is a strong base, HClO4 is a strong acid, the solution will be neutral.
Na2S + HOH ==> NaOH + H2S (not balanced), NaOH is a strong base, H2S is a weak acid, strong base wins out and the salt will be basic.
I hope this helps.
To determine which of the given salts will yield an acidic solution when dissolved in an aqueous solution, we need to consider the nature of the ions that are formed when these salts dissociate. Specifically, we should focus on the behavior of the cations (positive ions) and anions (negative ions) that are present in the salts.
1. NH4Cl (Ammonium chloride): When NH4Cl dissociates in water, it produces NH4+ cations and Cl- anions. The NH4+ ion has a positive charge, while the Cl- ion has a negative charge. Since NH4+ is derived from a weak acid (NH4OH, also known as ammonia), it can act as a weak acid in water, donating a proton (H+) to the solution. Hence, NH4Cl will yield an acidic solution.
2. NaClO4 (Sodium perchlorate): When NaClO4 dissociates in water, it produces Na+ cations and ClO4- anions. Both the Na+ and ClO4- ions are derived from strong acids (HClO4 and NaOH, respectively), which means they do not readily donate or accept protons in water. Therefore, NaClO4 will not affect the acidity of the solution, and the resulting solution will be neutral.
3. Na2S (Sodium sulfide): When Na2S dissociates in water, it forms Na+ cations and S2- anions. The S2- ion has a negative charge and can react with water to produce hydroxide ions (OH-) by abstracting a proton. Since hydroxide ions are basic, the solution resulting from Na2S is basic rather than acidic.
4. MgBr2 (Magnesium bromide): When MgBr2 dissociates in water, it yields Mg2+ cations and Br- anions. Neither of these ions acts as an acid or a base in water, so MgBr2 will not affect the acidity of the solution, and the resulting solution will be neutral.
5. Ba(CH3CO2)2 (Barium acetate): When Ba(CH3CO2)2 dissociates in water, it produces Ba2+ cations and CH3CO2- (acetate) anions. The acetate ion (CH3CO2-) is derived from a weak acid (CH3COOH, also known as acetic acid) and can participate in a hydrolysis reaction in water. This hydrolysis leads to the formation of additional H+ ions, resulting in an acidic solution.
In summary, among the given salts, NH4Cl and Ba(CH3CO2)2 will yield acidic solutions when dissolved in an aqueous solution.