Pressure (Lever)

Definition

The lever describing how external pressure works the carbonate equilibrium from the opposite end, with consequences that can leave the system entirely.

In open air, higher CO2 partial pressure drives more gas into solution (Henry’s Law), pushing the equilibrium toward the acid side, lowering pH and keeping carbonate scarce. Inside a boiler, pressure compounds what heat started: it pushes thermal bicarbonate breakdown further, converts carbonate to hydroxide, and releases still more CO2 that rides out with the steam. That CO2 re-dissolves in condensate as carbonic acid a pipe-length away, turning harmless feedwater alkalinity into downstream corrosion.

Related concepts

Henry’s Law · Temperature (Lever) · Condensate Corrosion

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Part of The Blueprint of Water · 🔥 thermodynamics