Each period represents once a principal energy level has been reached for an element.
Answer:
Butanoic acid present in solution
Explanation:
In this case, we have a buffer solution of butanoic acid and sodium butanoate. In other words a reaction like this:
HC₄H₇O₂ + H₂O <------> C₄H₇O₂⁻ + H₃O⁺ Ka = 1.5x10⁻⁵
The low value of Ka means that this is a weak acid. So, after this, the NaOH is added to the solution.
The NaOH is a really strong base, so we might expect that the pH of the solution increase drastically, however this do not occur.
The reason for this is because the first thing to happen in this reaction is an acid base reaction.
The NaOH react with the butanoic acid still present in solution, because is a weak acid, so in solution, this acid is not completely dissociated into it's respective ions. So the butanoic acid reacts with the NaOH and the products:
HC₄H₇O₂ + NaOH <------> Na⁺C₄H₇O₂⁻ + H₂O
So, because of this, the pH increase but not much.
3.16 X 10^-11 M is the [OH-] concentration when H3O+ = 1.40 *10^-4 M.
Explanation:
data given:
H30+= 1.40 X 10^-4 M\
Henderson Hasslebalch equation to calculate pH=
pH = -log10(H30+)
putting the values in the equation:
pH = -log 10(1.40 X 10^-4 M)
pH = 3.85
pH + pOH =14
pOH = 14 - 3.85
pOH = 10.15
The OH- concentration from the pOH by the equation:
pOH = -log10[OH-]
10.5= -log10[OH-]
[OH-] = 10^-10.5
[OH-] = 3.16 X 10^-11 is the concentration of OH ions when hydronium ion concentration is 1.40 *10^-4 M.
