passwella.
Menu

JAMB Chemistry 1986 Question 38

Question 38

Qualitative Analysis

A white solid suspected to be lead trioxonitrate (V), zinc trioxocarbonate (IV) or calcium trioxocarbonate (IV) was heated strongly. Its residue which was yellow when hot and white when cold is

  1. A.lead (II) oxide
  2. B.calcium oxide
  3. C.zinc oxide
  4. D.lead nitrate
Show the answer and explanation

Answer: C (zinc oxide)

Explanation

Zinc oxide is the residue that is yellow when hot and white when cold. Lead (II) oxide is reddish-brown hot and yellow cold, and calcium oxide stays white.