Phosphoric acid ($\text{H}_3\text{PO}_4$) ionizes in three distinct steps, each characterized by an ionization constant: $K_{a_1}$, $K_{a_2}$, and $K_{a_3}$. Additionally, there is an overall ionization constant denoted as $K$. Here is a breakdown of the key points:

Strength of Acidity: $\text{H}_3\text{PO}_4$ is a stronger acid compared to its subsequent ionized forms, $\text{H}_2\text{PO}_4^-$ and $\text{HPO}_4^{2-}$.

Ionization Constants:

$ \begin{array}{ll} \text{H}_3\text{PO}_4(\text{aq}) \rightleftharpoons \text{H}^+(\text{aq}) + \text{H}_2\text{PO}_4^-(\text{aq}) & K_{a_1} = 7.5 \times 10^{-3} \\ \text{H}_2\text{PO}_4^-(\text{aq}) \rightleftharpoons \text{H}^+(\text{aq}) + \text{HPO}_4^{2-}(\text{aq}) & K_{a_2} = 6.2 \times 10^{-8} \\ \text{HPO}_4^{2-}(\text{aq}) \rightleftharpoons \text{H}^+(\text{aq}) + \text{PO}_4^{3-}(\text{aq}) & K_{a_3} = 1.7 \times 10^{-12} \end{array} $

Relationship between Constants:

The relationship among the ionization constants follows the order: $K_{a_1} > K_{a_2} > K_{a_3}$.

The logarithmic expression of the overall ionization constant is given as:

$ \log K = \log K_{a_1} + \log K_{a_2} + \log K_{a_3} $

This information aligns with the conclusion that statements A, B, and C are accurate regarding the behavior of phosphoric acid and its ionization constants.