question_answer 32)

Which of the following property is generally not shown by metals? (a) Electrical conduction                                                                (b) Sonorous in nature  (c) Dullness                                                         (d) Ductility

Answer:

                    (c) A metal has a shining surface only when it is fresh. The metals lose their shine or brightness on keeping in air for a long time and acquire a dull appearance due to the formation of a thin layer of oxide, carbonate or sulphide on their surface. If we rub the dull surface with a sand paper, the metal objects become shiny and bright once again.