Question

A shiny brown coloured element ‘X’ on heating in air becomes black in colour. Name the element ‘X’ and the black coloured compound formed.


NCERT Class 10th Science Chapter 1 Chemical Reactions and Equations

Answer 1

Answer:

The element 'X' is Copper and the colored compound is Copper Oxide.

Explanation:

• The shiny element is a metal called Copper.
• It is the element that undergoes oxidation when heated in air.
• The copper reacts with the oxygen to produce a black-colored compound called copper oxide.
• The equation of this reaction is-

$2Cu + O_{2}$ → $2CuO$

2 moles of copper react with 1 mole of oxygen molecules to produce 2 moles of copper oxide.

Conclusion:

The shiny element is copper and the compound formed is copper oxide.

Answer 2

Answer:

Name the element 'X' and the black coloured compound formed.

Copper is a shiny brown coloured element. It gets oxidised to CuO , which is a black coloured substance , on reaction with Oxygen present in air. Hence, the substance 'X' is Copper (Cu)