An ammonia buffer contains NH₃:NH₄⁺ in a ratio of 0.4 moles:0.6 moles (pK = 9.75). What will be the pH if you add 0.01 moles of HCl to this buffer?

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The Henderson-Hasselbalch equation can be used to calculate the pH of a buffer solution:pH = pKa + log([A-]/[HA])where pKa is the acid dissociation constant, [A-] is the concentration of the conjugate base, and [HA] is the concentration of the weak acid.In this case, the pKa of the ammonia buffer is 9.75, and the ratio of [NH3] to [NH4+] is 0.4:0.6. This means that the concentration of NH3 is 0.4 moles/liter and the concentration of NH4+ is 0.6 moles/liter.If we add 0.01 moles of HCl to this buffer, the concentration of NH4+ will increase by 0.01 moles/liter and the concentration of NH3 will decrease by 0.01 moles/liter. This will shift the equilibrium to the left, resulting in a decrease in pH.The new pH can be calculated using the Henderson-Hasselbalch equation:pH = 9.75 + log([0.39 moles/liter]/[0.61 moles/liter]) = 8.98Therefore, the correct answer is A) 8.98.

An Ammonia Buffer Contains NH3:NH4+ in a Ratio of 0

An Ammonia Buffer Contains NH₃:NH₄⁺ in a Ratio of 0