Chapter 7 · Corrosion · Ten playable problems

PROBLEM 61 · CORROSION — THE FOUR COMPONENTS

Anode, cathode, electrolyte, metal path. In an open cooling tower, which cathodic reactant is effectively impossible to eliminate — and why?

PROBLEM 62 · CORROSION — FILM SABOTEURS

Passivation is not immunity — it is a ceasefire. Match each of the four saboteurs to how it breaks it.

PROBLEM 63 · CORROSION — GALVANIC COUPLING

A new carbon steel header is threaded straight onto existing copper piping — no dielectric union. Click the metal that corrodes preferentially.

PROBLEM 64 · CORROSION — CREVICE ATTACK

A gasket creates a crevice on a carbon steel flange in oxygenated water. Assign where the anode and cathode develop — then see why it accelerates.

PROBLEM 65 · CORROSION — MPY FROM WEIGHT LOSS

A carbon steel coupon spends 90 days in the tower: 12.4500 g in, 12.1500 g out. Work the MPY, dial it, and classify the water.

PROBLEM 66 · CORROSION — LARSON-SKOLD AT 6 CYCLES

Makeup: Cl⁻ 40, SO₄²⁻ 25, M-alkalinity 50. Cycle the tower up and watch the Larson-Skold ratio — then say what that reveals about bulk indices.

PROBLEM 67 · CORROSION — WHICH LEG DOES EACH WEAPON HIT

Every treatment attacks one leg of the cell. Pick a weapon, then click the leg it is aimed at.

PROBLEM 68 · CORROSION — CURRENT DENSITY

Same two metals, opposite geometry. Click the configuration that destroys its steel fastest.

PROBLEM 69 · CORROSION — FOUR CONDITIONS AT ONCE

Elevated chloride, intermittent low-pH excursions, biofilm deposits, 6 MPY coupon loss — all at once. Why do these multiply risk instead of merely adding it?

PROBLEM 70 · CORROSION — WHY A BREACH ACCELERATES

The passive film is breached. Current = Voltage ÷ Resistance — assign what happens to each term, and watch the current answer.