pH = -log10[H+] and Kw = [H+][OH-] = 1.0e-14. The pot solves the charge balance of every dissolved acid and base exactly (bisection), so weak acids buffer correctly. Red cabbage juice contains anthocyanins that change shape, and colour, as pH changes: red in acid, violet near 5-7, blue and green in alkali, yellow at the extreme. The colour table is a model, not a measuring instrument.

H+ + OH- gives H2O. A weak acid with its salt resists change: pH = pKa + log10([A-]/[HA]), so vinegar plus a little baking soda holds a violet pH of about 5. Near the equivalence point the pH jumps (25.0 mL titration: 3.70, 7.00, 10.30).

C1·V1 = C2·V2. Colour follows Beer-Lambert: A = ε·c·l, T = 10^-A summed over dyes, so doubling the dye squares the transmittance.

k = A·exp(-Ea/RT) with Ea = 50 kJ/mol. Heating from 25 to 35 °C multiplies k by 1.92. The anthocyanin bleaches by first order C = C0·e^(-kt), half-life t½ = ln2/k (600 s at 25 °C, game time is sped up 20 times).

CaCO3 + 2H+ → Ca2+ + H2O + CO2; 1 g of chalk gives 10.0 mmol and 245 mL of CO2 at 25 °C (24.5 L/mol). Heating: m·c·dT/dt = P - hA(T - Tenv), water stops at 100 °C while the extra power boils it away.

Ideal solutions (activity 1), pKa values at 25 °C, one effective dye per plant, citric acid treated as one weak acid, modelled colours (not measured), real anthocyanin bleaching usually needs a higher activation energy, and ingredient pH values are typical as-sold values. This lab is not affiliated with any brand or film.