Buffers and Titration Curves: Blood pH | General Chemistry 2.7

One milliliter of strong acid sends pure water from pH 7 to 3 but moves an acetic acid and acetate mixture by less than a hundredth, the same trick your blood plays near pH 7.4. This episode explains how a weak acid and its conjugate base soak up added acid, derives the Henderson-Hasselbalch equation in three steps, and covers buffer capacity and blood's bicarbonate buffer. It then builds a titration curve drop by drop, reads the pKa halfway to equivalence, and explains how indicators pick the endpoint. Chapters 0:00 Pure water against a buffer 1:51 The common-ion effect 2:47 How a buffer soaks up acid 3:46 Isolating the ratio from Ka 4:14 Henderson's equation, 1908 4:49 Taking logarithms 5:28 Testing the equation on the beaker 6:13 Buffer capacity 6:33 Choosing the ratio 7:13 Blood: a bicarbonate buffer 8:29 Glass electrodes and titration curves 8:49 A titration curve, step by step 11:04 Species fractions across the curve 11:52 Indicators 12:15 Indicator windows 12:55 Back to the two beakers 13:20 Three things to take away Reference: Steven S. Zumdahl and Susan A. Zumdahl, *Chemistry*, 7th ed, sections 15.1-15.5. Historical sources: Henderson, Am. J. Physiol. 21, 173 (1908): https://doi.org/10.1152/ajplegacy.190... Previous episode: 2.6 "Acids by Structure". Next episode: 2.8 "Solubility Products". Narration: AI voice (ElevenLabs); music: AI-generated (Lyria) and original synthesized tracks.