Q18 of 35 Page 42

A shiny brown colored element 'X' on heating in air becomes black in colour. Can you predict the element ‘X’ and black colored substance filmed? How do you support your predictions? (AS2)

⇒It is given that ‘X’ is a shiny brown colored element. This means ‘X’ is a copper metal.

⇒When copper (X) is heated in air, it becomes black in color due to the deposit of copper oxide on its surface.


⇒The reaction takes place:


2Cu + O2→ 2CuO


Brown Black


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