Corrosion and Its Prevention MCQs

Q1. Which method protects iron with a coating of a LESS reactive metal acting only as a barrier?

• A.cathodic protection
• B.sacrificial protection
• C.tinning
• D.galvanising

Answer: C. tinning

Quick parse - a typical chemistry numerical. We are after the quantity the stem asks for. Tool of choice - hence the answer = tinning. Rearrange it for the unknown before substituting. Common-sense check: the reactivity series runs K > Na > Ca > Mg > Al > Zn > Fe > Pb > (H) > Cu > Hg > Ag > Au. Lock in option C) tinning. Trap-watch: option A) 'cathodic protection' doesn't hold - That uses a more reactive anode metal; option B) 'sacrificial protection' is incorrect: That uses a more reactive metal.

Q2. Which is NOT a method of preventing corrosion of iron?

• A.greasing
• B.painting
• C.keeping it in a damp store-room
• D.galvanising

Answer: C. keeping it in a damp store-room

Q3. Consider the following statements about corrosion and its prevention: (I) Rusting requires both oxygen and moisture. (II) Galvanisation uses a zinc coating. (III) Painting increases the rusting of iron. Which of the above statement(s) is/are correct?

• A.Only I and II
• B.Only I
• C.None of these
• D.Only III

Answer: A. Only I and II