Write a balanced equation for the proton transfer reaction between water and phosphate ion. Determine in which direction the equilibrium is favored.
HOH + PO4^3- ==> HPO4^2- + OH^-
Products are favored. Do you know why?
I want to say because it has more of the reactant. Am I right?
I think I want to change my answer. I believe the reactants are favored.
Calculate the Kb for the base.
PO4^3- + HOH ==> HPO4^2- + OH^-
Kb for PO4^3- = (Kw/k3 for H3PO4) = 1E-14/4.2E-13 = about 0.024. Even though 0.024 is a "relatively" large number in Kb terms (and PO4^3- is a strong base in terms of pH), it is less than 1 which means the numerator is small and the denominator is large. That means that the reactants predominate at equilibrium.
To write a balanced equation for the proton transfer reaction between water (H2O) and the phosphate ion (PO4^3-), we need to consider the proton transfer between them.
The phosphate ion has a charge of -3 and needs three protons to balance its charge. Water acts as an acid in this reaction by donating a proton (H+) to the phosphate ion. Thus, the balanced equation can be written as:
H2O + PO4^3- → HPO4^2- + OH-
Now, let's determine in which direction the equilibrium is favored. In this reaction, the forward direction involves water donating a proton to the phosphate ion, forming the hydrogen phosphate ion (HPO4^2-) and hydroxide ion (OH-).
The equilibrium is favored in the forward direction when there is a high concentration of water or a low concentration of hydrogen phosphate ion and hydroxide ion. This is because the forward reaction involves the consumption of water and the production of the hydrogen phosphate ion and hydroxide ion.
On the other hand, if there is a high concentration of hydrogen phosphate ion or hydroxide ion, the equilibrium will shift in the reverse direction to consume these ions and produce more water molecules.
Therefore, the equilibrium is favored in the forward direction when there is a high concentration of water or a low concentration of hydrogen phosphate ion and hydroxide ion.