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# Volume of an acid required to change the pH of a buffer solution

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What volume (in mL) of 0.37M HCI solution must be added to 265.00 mL 0.29M ammonia solution to give a buffer solution with pH 9.1? (Kb for ammonia 1.80e-5) 1.80 x10^-5

https://brainmass.com/chemistry/acids-and-bases/volume-acid-required-change-ph-buffer-solution-4341

#### Solution Preview

The equation to calculate the pH of a buffer solution is:
pH = pKa - log [HA]/[A-]
The most important thing here is to recognize what our buffer system is. This is going to be an NH4+/NH3 buffer, where the acid component is NH4+ (HA), and the base component or the "anion" is NH3. Only NH4+ can be HA, i.e. an acid (we're looking for a weak acid), because NH4+ can lose a proton and become NH3. The pKa of a conjugate acid formed from a base (in this case NH4+ formed from NH3 can be calculated from the ...

#### Solution Summary

Full solution using the equation to calculate the pH of a buffer solution is pH = pKa - log [HA]/[A-]. 400 words.

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