Solution:Concept- The colour of zinc oxide when it is hot is yellow. Although zinc oxide is a white powder when pure, it is more commonly found in nature as the rare mineral zincite, which typically has manganese and other impurities that give it a yellow to red hue.
zinc oxide is amphoteric (reacts with acids and bases) and has the chemical formula .
It looks like a white powder and is insoluble in water. It is found in the earth's crust as zincite.
Now, Zinc oxide is thermochromic in its crystalline state, turning from white to yellow when heated and turning white when cooled.
Hence, the correct answer is yellow.