For the titration of a dibasic weak acid H2 A(p^Ka(2)-p^Ka(1) ≥2) with a strong base, pH versus

step 1 Using the formula pv equals NRT, we can determine the number of moles of carbon dioxide, substit

For the titration of a dibasic weak acid H2...

For the titration of a dibasic weak acid $\mathrm{H}_{2} \mathrm{~A}\left(p^{K_{\mathrm{a}(2)}}-p^{K_{a(1)}} \geq 2\right)$ with a strong base, $\mathrm{pH}$ versus volume of the base graph is as shown in the figure. $p^{K_{a(1)}}$ and $p^{K_{42}}$ are equal to the $\mathrm{pH}$ values corresponding to the points:. (a) B and D, respectively (b) A and B, respectively (c) $\mathrm{C}$ and $\mathrm{D}$, respectively (d) A and C, respectively

For the titration of a dibasic weak acid $\mathrm{H}_{2} \mathrm{~A}\left(p^{K_{\mathrm{a}(2)}}-p^{K_{a(1)}} \geq 2\right)$ with a strong
base, $\mathrm{pH}$ versus volume of the base graph is as shown in the figure. $p^{K_{a(1)}}$ and $p^{K_{42}}$ are equal to the $\mathrm{pH}$ values corresponding to the points:.
(a) B and D, respectively
(b) A and B, respectively
(c) $\mathrm{C}$ and $\mathrm{D}$, respectively
(d) A and C, respectively

Key Concepts

Acid-Base Titration

This technique involves the gradual addition of a titrant of known concentration to react with an analyte, allowing for the determination of the analyte’s concentration and properties. In the context of acid-base reactions, tracking the pH change as titrant is added provides insights into the acid-base behavior of the substance being titrated.

Polyprotic Acid Titration

Polyprotic acids, which can donate more than one proton, undergo a series of deprotonation steps, each associated with its own dissociation constant (pKa). The titration of such acids typically shows multiple stages or equivalence points, each corresponding to the neutralization of a proton.

pKa Values

The pKa of an acid is the negative logarithm of its acid dissociation constant and serves as an indicator of the acid’s strength. In titration curves, the pKa is particularly significant at the half-equivalence point, where the concentrations of the acid and its conjugate base are equal, causing the pH to equal the pKa.

Equivalence Points and Half-Equivalence Points

The equivalence point in a titration is reached when the amount of titrant added exactly neutralizes the acid present. In polyprotic acid titrations, multiple equivalence points occur corresponding to each deprotonation step. Half-equivalence points, on the other hand, are found at the midpoint of each titration step, where the pH equals the pKa of the particular proton being titrated.

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