Electrochemical Corrosion MCQs : Here you will find MCQ Questions related to "Electrochemical Corrosion" in Corrosion Engineering. These Electrochemical Corrosion MCQ Questions Will help you to improve your Corrosion Engineering knowledge and will prepare you for various Examinations like Competitive Exams, Placements, Interviews and other Entrance Exmaniations
Which of the following true about Electrochemical corrosion?
A. Electrochemical corrosion of metals occurs when proton from atoms at the surface of the metal are transferred to a suitable proton acceptor or depolarizer.
B. Electrochemical corrosion of metals occurs when neutron from atoms at the surface of the metal are transferred to a suitable neutron acceptor or depolarizer.
C. Electrochemical corrosion of metals occurs when electrons from atoms at the surface of the metal are transferred to a suitable electron acceptor or depolarizer.
D. All of the above
Explanation: Electrochemical corrosion of metals occurs when electrons from atoms at the surface of the metal are transferred to a suitable electron acceptor or depolarizer.
__________ must be present to serve as a medium for the transport of ions.
Explanation: Water must be present to serve as a medium for the transport of ions.
The most common depolarizers are?
D. Both A and B
Explanation: The most common depolarizers are oxygen, acids, and the cations of less active metals.
Corrosion of steel can be inhibited by galvanizing
C. Can be yes or no
D. Can not say
Explanation: Corrosion of steel can be inhibited by galvanizing, that is, by coating it with zinc, a more active metal whose dissolution leaves a negative charge on the metal which inhibits the further dissolution of Fe2+.
Which of the following are the types of chemical reactions?
A. Combination and Decomposition reactions
B. Combination and Single displacement
C. Single and Double displacement reaction
D. Combination, Decomposition, Single displacement and double displacement
Explanation: Combination reaction: A+B==>C,
Decomposition reaction: A==>B+C,
Single displacement reaction: AB+C==>AC+B
Double displacement reaction: AB+CD==>AC+BD
Which of the following parameter of electrolyte decreases the corrosion rate?
A. Dissolved oxygen
C. High electrical resistance
D. Presence of ferric ions
Explanation: The Function of an electrolyte is to transfer the ions between anode and cathode. Increase in electrical resistance in electrolyte shows obstruction for the free flow of ions, hence the corrosion rate decreases. Whereas dissolved oxygen, temperature and presence of ferric ions increases the mobility of ions and increases the corrosion rate.
Polarization is the potential difference occurred due to the non-equilibrium conditions?
C. Can be true or false
D. Can not say
Explanation: Polarization is the potential difference occurred due to the non-equilibrium conditions, due to the change in concentration or temperature. These are classified into three types. They are i) Activation polarization ii) Concentration polarization iii)Resistance polarization.
What is meant by passivation?
A. Loss of reactivity
B. Increase in reactivity
C. Increase in corrosion rate
D. Deterioration of metal
Explanation: Passivation is the state of metal in which stable films or barriers are formed. These stable films obstruct the contact of corrosive medium to the metal surface. Most of the engineering metals undergo passivation under different atmospheric conditions.
Which of the following is denoted as // in an electrochemical cell notation?
B. Salt bridge
Explanation: Salt bridge is a connection between two half cells used to neutralize the ions with respective opposite charged ions. Usually, strong electrolytes such as KCl along with agar-agar gel are used.
Which of the following polarization will be influenced by electrolytic agitation?
A. Activation polarization
B. Resistance polarization
C. Concentration polarization
D. Both Activation and Resistance polarization
Explanation: Concentration polarization refers to the electrochemical reaction that is controlled by the diffusion of ions in an electrolyte. With an increase in the velocity or agitation of the electrolyte the contact of ions with metal interface increases.