Question

The metal oxide is yellow when hot and white when cold.The metal oxide is

Answer 1

Metal oxide:

• A metal oxide is a crystalline solid that is composed of a metal cation and an oxide anion.
• Metallic oxide is alkaline in nature.
• Almost all metals combine with oxygen to form metal oxides.
• General reaction for the formation of metal oxide:

$\mathrm{Metal}+\mathrm{Oxygen}\to \mathrm{Metal}\mathrm{oxide}$

The metal oxide is yellow when hot and white when cold. The metal oxide is Zinc oxide.

Zinc oxide:

• Zinc oxide is amphoteric in nature.
• Zinc oxide reacts with a strong base to form zincates, when this is strongly heated it assumes a yellow color which disappears when it is cooled down.
• The chemical reaction can be depicted as:

$\mathrm{ZnO}\left(\mathrm{aq}\right)+2\mathrm{NaOH}\left(\mathrm{aq}\right)\to {\mathrm{Na}}_2{\mathrm{ZnO}}_2\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$