How do you know if these solutions are acidic, basic, or nearly neutral?
a. NH4NO2
b. Cr(NO3)3
Hydrolyze salts to make that determination.
NH4NO2 + HOH ==> HNO2 + NH4OH
Note that HNO2 is a weak acid and NH4OH actually is NH3 + H2O (a weak base); therefore, the decision rests upon which is stronger, the weak acid or the weak base. The (H^+) of solutions of salts that are salts of weak acids AND weak bases = sqrt(KwKa/Kb). Look up Ka and Kb, substitute, convert H to pH and you have your answer. OR, just pH = pKw + pKa - pKb. (P. S. I don't see this question much--this formula was taught to me when I took analytical chemistry but I don't see it much in books anymore). Fortunately I still remember it after 60 years.
The second one is simpler.
Cr(NO3)3 + 3HOH ==> Cr(OH)3 + 3HNO3
Cr(OH)3 is a weak base. HNO3 is a strong acid; therefore, the solution will be acidic.
All of this type question hinges on how the hydrolysis equation looks. I suggest you write them even though you think neither anion nor cation is hydrolyzed.
Here are examples of the four types.
NaCl + HOH ==> NaOH + HCl
NaOH is strong base, HCl a strong acid, solution is neutral
NH4Cl + HOH ==> NH4OH + HCl
NH4OH (NH3 + HOH) is a weak base, HCl a strong acid, solution is acidic.
NaC2H3O2 (sodium acetate).
NaAc + HOH ==> NaOH + HAc.
NaOH is a strong base, HAc a weak acid, solution is basic.
NH4Ac + HOH ==> NH4OH + HAc
Kb NH3 = 1.8 x 10^-5
Ka HAc = 1.8 x 10^-5
(H^+) = (KwKa/Kb). Since Ka = Kb soln is neutral. If Ka is stronger soln is acid. If Kb is stronger, soln is basic.
How can i get Factor of 1.666 for multipling to Mn
To determine if a substance is acidic, basic, or nearly neutral, you can look at the chemical formula and the individual ions present in the compound.
a. NH4NO2:
To determine the acidity or basicity of NH4NO2, we need to consider the individual ions present. NH4+ is the ammonium ion, which is acidic. NO2- is the nitrite ion, which can act as a weak acid or weak base depending on the solution's pH. In this case, as NH4+ is acidic, NH4NO2 will be acidic overall.
b. Cr(NO3)3:
Cr(NO3)3 is made up of the chromium cation (Cr3+) and nitrate anions (NO3-). The chromium cation (Cr3+) has no acidic or basic properties. Nitrate anions (NO3-) are typically considered neutral. Therefore, Cr(NO3)3 is nearly neutral.
To determine if a solution is acidic, basic, or nearly neutral, we need to examine the chemical formula and the nature of the ions present in the solution.
a. NH4NO2:
For NH4NO2, we first need to break it down into its component ions. NH4NO2 breaks down into NH4+ and NO2- ions. The NH4+ ion comes from ammonium (NH4+) and the NO2- ion comes from nitrite.
Ammonium (NH4+) is a weak acid that tends to release a proton (H+) in solution, making it slightly acidic. Nitrite (NO2-) is considered a basic anion.
In this compound, the presence of both an acidic and a basic ion suggests that the solution will be nearly neutral.
b. Cr(NO3)3:
Cr(NO3)3 consists of chromium (Cr3+) cations and nitrate (NO3-) anions.
The chromium ion (Cr3+) does not have any hydroxide ions associated with it that would make it basic. Nitrate (NO3-) on the other hand, is known to be a weak base.
Since we do not have any acidic ions, and one basic ion (nitrate) in the compound, the solution can be expected to be slightly basic.
In summary:
a. NH4NO2: The solution is nearly neutral.
b. Cr(NO3)3: The solution is slightly basic.