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# PH and Molar Solubility

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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?

https://brainmass.com/chemistry/physical-chemistry/113100

#### Solution Preview

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 ...

#### Solution Summary

Three questions on pH and Molar Solubility are solved in this posting.

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