PH and Molar Solubility. See attached for full problem description.
12. What is the pH of a 650 mL solution that contains 250g of HNO2 and 100g NaNO2?
13. What is the molar solubility of MnCO3 if 5.3 x 10^-5 M Na2CO3 is added to the solution?
14. What is the pH of a solution after titrating 200mL of 0.100 M NH2OH to the equivalence point with 200mL of 0.100 M HCl?© BrainMass Inc. brainmass.com March 4, 2021, 7:38 pm ad1c9bdddf
12. For this questions, I would really like you to be able to recognize it as a buffer type question, and the easiest to recognize. It is a mixture of a weak acid HNO2 and it's conjugate base NaNO2 (since NaNO2 dissolves to make Na+ + NO2-). Set this problem up according to the buffer formula shown below:
Ka = [H+] x A-/HA
Where Ka is the acid dissociation constant for the acid HA
[H+] is the term you will use to find the pH
A- is the moles of conjugate base
HA is the moles of the acid
You should have a table with all the Ka values listed, so find your table and use that value, but you will have to calculate the moles of both ...
Three questions on pH and Molar Solubility are solved in this posting.