Determine whether each cation is acidic or pH neutral. For those cations that are acidic, write an equation that shows how the cation acts as an acid.
A) Sr+2
B) Mn+3
C) C5H5NH+
D) Li+
To determine whether each cation is acidic or pH neutral, we need to consider the behavior of each cation when it is dissolved in water. Acidic cations are those that can donate a proton (H+) to water, thereby increasing the concentration of H+ ions and decreasing the pH.
A) Sr+2:
Strontium (Sr) is an alkaline earth metal, and typically metals form basic cations. Therefore, the Sr+2 cation is pH neutral and does not act as an acid.
B) Mn+3:
Manganese (Mn) is a transition metal, and its cations can have different acid-base properties depending on their oxidation state. In this case, the Mn+3 cation has a +3 charge. Since the +3 charge on the cation is relatively small, it can attract water molecules and donate a proton to water, making it an acidic cation. The equation for the reaction of Mn+3 acting as an acid can be written as:
Mn+3 + H2O → Mn+2 + H3O+.
C) C5H5NH+:
This cation is a protonated form of pyridine, a weak base. When it is dissolved in water, it can accept a proton from water, making it pH neutral. Therefore, the C5H5NH+ cation is pH neutral and does not act as an acid.
D) Li+:
Lithium (Li) is a metal and typically forms basic cations. Therefore, the Li+ cation is pH neutral and does not act as an acid.
In summary:
A) Sr+2: pH neutral (not an acid)
B) Mn+3: acidic (acting as an acid)
C) C5H5NH+: pH neutral (not an acid)
D) Li+: pH neutral (not an acid)
To determine whether each cation is acidic or pH neutral, we need to examine their behavior in water. If a cation acts as an acid, it will donate a proton (H+) to water and increase the concentration of H+ ions, making the solution acidic.
Let's analyze each cation individually:
A) Sr+2:
Strontium ion (Sr+2) is not acidic. It does not donate a proton to water and does not increase the concentration of H+ ions. Therefore, Sr+2 is pH neutral.
B) Mn+3:
Manganese(III) ion (Mn+3) can act as an acid. It donates a proton (H+) to water, increasing the concentration of H+ ions in the solution. The equation for its acidity can be written as follows:
Mn+3 + H2O → Mn+2 + H3O+
C) C5H5NH+:
The cation C5H5NH+ is a protonated form of pyridine. It can also act as an acid by donating a proton (H+) to water, increasing the concentration of H+ ions. The equation for its acidity can be written as follows:
C5H5NH+ + H2O → C5H5N + H3O+
D) Li+:
Lithium ion (Li+) is not acidic. It does not donate a proton to water and does not increase the concentration of H+ ions. Therefore, Li+ is pH neutral.
A) Neutral
B)Acidic
C)Acidic
D) Neutral