Question

Assertion: Iron is protected from corrosion by connecting magnesium metal with it.
Reason: Iron acts as cathode and magnesium as anode which gradually disappear.
A.Both assertion and reason are correct and reason is the correct explanation of assertion
B.Both assertion and reason are correct but reason is not the correct explanation for assertion
C.Assertion is correct but reason is incorrect
D.Both assertion and reason are incorrect

Answer 1

Hint: A metal can be protected from corrosion by using a more reactive metal than the metal which has more oxidation electrode potential than iron. Oxidation occurs at anode.

Complete step by step answer:
-The method used to protect iron from corrosion with the help of some other metal is known as cathodic protection or sacrificial protection. Corrosion occurs due to the reaction of iron or oxidation of iron with the air and moisture of the surrounding.
-If we connect iron with some other metal, which is more reactive than iron then a difference in electrode potential will arise and it will form a galvanic cell. The metal with higher oxidation potential then iron will oxidize itself and keep iron safe from corrosion that is why it is known as sacrificial protection.
-Always, oxidation occurs at anode and reduction occurs at cathode. The magnesium is being oxidized because of its higher oxidation electrode potential than iron and hence magnesium will act as anode and iron as cathode.
 So both assertion and reason are correct and the reason is a correct explanation for the assertion.

Hence, the correct option is option A.

Note:
Electrode potential is the ability of an element to gain or lose electrons when it is placed in the solution of its own ion. The element can either gain electrons, lose electrons or remain unaffected. If an element gains electrons it is said to be reduced and the process of gaining electrons is known as reduction. If an element loses electrons then it is said to be oxidized and the process of losing electrons is known as oxidation.