The relative reactivity of zinc and its ability to attract oxidation to itself makes it an efficient sacrificial anode in cathodic protection (CP). For example, cathodic protection of a buried pipeline can be achieved by connecting anodes made from zinc to the pipe. Zinc acts as the anode (negative terminus) by slowly corroding away as it passes electric current to the steel pipeline.[note 2] Zinc is also used to cathodically protect metals that are exposed to sea water from corrosion. A zinc disc attached to a ship's iron rudder will slowly corrode, whereas the rudder stays unattacked. Other similar uses include a plug of zinc attached to a propeller or the metal protective guard for the keel of the ship. COUNT 4
QSN1 What makes zinc an efficient sacrificial anode? ANS1 relative reactivity of zinc and its ability to attract oxidation QSN2 Connecting anodes made from zinc to buried pipe creates what? ANS2 cathodic protection QSN3 What does attaching a zinc disc to a ships iron rudder do? ANS3 protect metals that are exposed to sea water from corrosion QSN4 Why does zinc protect metals exposed to sea water from corroding? ANS4 will slowly corrode, whereas the rudder stays unattacked