Showing posts from September, 2016

Salt Bridge in Voltaic cell

 Q: Why we use Salt bridge in Voltaic cell?

Ans:  Salt Bridge keeps the solution (electrolyte) of the electrodes neutral by providing a pathway for migration of ions.

Wants to know More!

Fine Silver

Q:    Why pure or fine silver is not often used to make jewelries?

Ans:   Because pure or fine Silver is very malleable, soft and can be easily damaged and is very costly.

Electroplating of Zinc

Q: In electroplating of zinc, Why the target(object) is cleaned first in alkaline solution and then treated with acid?

Ans:     To remove any dust particle or rust scales from that object, the target (object) is cleaned first in alkaline solution and then treated with acid.

Electroplating 0f Chromium

Q:      Why steel is first plated with Nickle or Copper in electroplating of Chromium?

Ans:     Because Chromium does not adheres well on the surface of steel. To make the surface of steel adhesive, steel is usually plated first with Nickel or Copper in electroplating of Chromium.

Coated iron

Q: Why tin Plated iron rusted rapidly when tin layer is broken while zinc coated iron does not rust even after the coating surface is broken?

Ans:     The oxidation potential of Tin (Sn) is less than that of Zinc (Zn). That is why after when the surface is broken, Tin cannot provide electrons effectively while Zinc can provide electrons to iron not allowing it to be oxidized. Tin protects the iron only as long as its protective layer remains intact with iron while Zn protects the iron against corrosion even after the coating surface is broken.

Paint, grease and oil prevent corrosion

Q: How paint, grease and oil prevent corrosion?

Ans:    Paint, grease and oil are organic compounds having high molecular weight. When these compounds are applied on metal surface, they adhere to it and due to their non-polar nature they are not dissolved in water. Thus these compounds will not allow water and H+ to be in direct contact with metal.

Coating of Metals

Q:    Why we paint grease, coat metals or why we make metal alloy?

 Ans:    We paint, grease, coat metals or we make them alloys to prevent them from corrosion. Paint, grease, being non polar have no affinity for moist air and due to this unique property prevents metal from corrosion.