Calculate the ratio of the masses of the buffer components required to make the buffer.?

Question

For the best system, calculate the ratio of the masses of the buffer components required to make the buffer. (Kb(NH3)=1.76×10−5.)
Express your answer using two significant figures.

hcbiochem · Answer

You have not identified what the compound that provides the conjugate acid of NH3 is. It might be NH4Cl, or any other compound that on dissolving forms NH4+ ions. You also don't give a pH of the final buffer. However, with the pH, you can calculate the molar ratio as follows:

NH3 + H2O <--> NH4+ + OH-

Kb = 1.76X10^-5 = [NH4+][OH-]/[NH3]

Now, use the pH to calculate pOH and the [OH-]
pOH = 14.00 - pH
[OH-] = 10^-pOH

Now, plug the [OH-] into the equation for Kb, and calculate [NH4+]/[NH3]

Now, to get to your answer, multiply that ratio by (molar mass of compound providing NH4+ / molar mass NH3.

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Calculate the ratio of the masses of the buffer components required to make the buffer.?

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