In cach pair, sclcct the strongcr acid. (a) Pyruvic acid \(\left(\mathrm{p} K_{\mathrm{a}} 2.49\right)\) and lactic acid \(\left(\mathrm{p} K_{\mathrm{a}} 3.08\right)\) (b) Citric acid \(\left(\mathrm{p} K_{\mathrm{a} 1} 3.08\right)\) and phosphoric acid \(\left(\mathrm{p} K_{\mathrm{a} 1} 2.10\right)\)

Understanding the strength of an acid can be critical in predicting its behavior in chemical reactions, and one of the most reliable indicators of acid strength is the pKa value. The term pKa is derived from the acid dissociation constant, Ka, and provides a scale for measuring the tendency of an acid to donate a proton (H+).

In essence, the pKa value is a logarithmic scale and inversely relates to the strength of the acid: the lower the pKa value, the stronger the acid. When comparing acids, as in the given textbook exercise, we can immediately see that pyruvic acid with a pKa of 2.49 is stronger than lactic acid, which has a pKa of 3.08. This is because pyruvic acid is more willing to donate its proton, which is reflected in its lower pKa value.

Understanding pKa values also allows us to predict how acids will behave in different environments, such as biological systems or industrial chemical processes. It's vital for students to grasp that pKa is not just a number, but a conceptual tool that helps to understand acid-base interactions succinctly.

Acid-base chemistry is one of the cornerstones of chemical education, explaining how substances donate and accept protons. At the heart of this topic is the concept of acid and base strength. Acids are proton donors, and bases are proton acceptors. The strength of an acid or base is determined by its ability to donate or accept protons, respectively.

Strong acids fully dissociate in water, releasing all of their protons, while weak acids only partially dissociate. In the provided exercise, by comparing the pKa values of the acids, we indirectly compare their dissociation tendencies in water. The strength of phosphoric acid (pKa1 of 2.10) compared to citric acid (pKa1 of 3.08) indicates that phosphoric acid donates protons more readily, making it the stronger acid.

Understanding the principles of acid-base chemistry is essential not only in a laboratory setting but also in real-world applications such as pharmaceuticals, environmental science, and nutrition. It's a foundational concept that students must understand thoroughly to progress in their chemical education.

Organic acids are a group of compounds that contain carbon and exhibit acidic properties. They play vital roles in organic chemistry and are prevalent in many biological processes. The strength of an organic acid can depend on several factors, including the presence of electron-withdrawing groups, the stability of the conjugate base, and intramolecular hydrogen bonding.

In the given exercise, both pyruvic acid and lactic acid are organic acids. Pyruvic acid has a ketone group, which is an electron-withdrawing group. This group stabilizes the negative charge on the conjugate base after the acid donates its proton. Lactic acid lacks this electron-withdrawing group, making its conjugate base less stable and, therefore, a weaker acid. This information enhances the step-by-step solution by explaining why pyruvic acid is the stronger acid based on structural features, beyond just the numerical pKa comparison.

Organic acids are found in a myriad of environments, from the citric acid in fruits to the lactic acid in muscles. They are also essential in industrial applications like the manufacturing of plastics, pharmaceuticals, and food preservatives. A profound understanding of organic acid properties is necessary for students aiming to apply chemistry in both academic and practical settings.