24. Chemical action during corrosion converts metal into metallic component as: a. hydroxide b. oxide C. sulphate 25. Which of the following corrosions are caused due to velocity of fluid flow in pipes? d. Intergranular b. Cavitation corrosion c. galvanic corrosion a. Bimetal corrosion corrosion 26. Pourbaix diagram is a graphical plot of (a) Emf Verses pH (b)Emf Verses Logi (c) Emf Verses time (d) Current Verses Potential 27. Passivity in stainless steel is due to the formation of (a) sulphide film (b) carbide film 28. Iron pipe carrying $ater is more anodic to copper. This is due to (a) concentration cell (b) Galvanic cell (c) electrolytic cell 29. This occurs when two surfaces fit tightly together but can move relative to one another, resulting in constant rubbing and abrasive wear (a) Types of Corrosion (b) Stress Corrosion (c) Pitting Corrosion (d) Fretting Corrosion 30. Also known as dry corrosion, this occurs when a metal such as aluminum is exposed to a gas containing oxygen, a chemical reaction takes place on the surface between the metal and the gas. (a) lon (b) Electron d. all of the above (c) Oxide film (d) chloride film (c) Proton (d)Oxidation