Question

Devon’s laboratory is out of material to make phosphate buffer. He is considering using sulfate to make a buffer instead. The pka values for the two hydrogens in H2SO4 are -10 and 2.
Will this approach work for making a buffer effective near a pH of 7?
O yes
O not enough information to answer
O no
What is the optimal pH for sulfate‑based buffers? Enter your answer as a whole number.

Answer 1

Answer:

Is not possible to make a buffer near of 7.

Optimal pH for sulfate‑based buffers is 2.

Explanation:

The dissociations of H₂SO₄ are:

H₂SO₄ ⇄ H⁺ + HSO₄⁻ pka₁ = -10

HSO₄⁻ ⇄ H⁺ + SO₄²⁻ pka₂ = 2.

The buffering capacity is pka±1. That means that for H₂SO₄ the buffering capacity is in pH's between -11 and -9 and between 1 and 3, having in mind that pH's<0 are not useful. For that reason, is not possible to make a buffer near of 7.

The optimal pH for sulfate‑based buffers is when pka=pH, that means that optimal pH is 2.

I hope it helps!