Lead monoxide is not used in the laboratory preparation of lead sulphate. Why?!
Answers
Answer:
Lead sulfate is insoluble, when lead is added to sulfuric acid it only reacts on the surface. The lead becomes coated with insoluble lead sulfate and the lead in the interior can't react. Therefore lead sulfate cannot be prepared by adding dilute sulfuric acid.
Answer:
Lead monoxide is poorly soluble in water. The solubility of lead monoxide in dilute sulfuric acid is also very low. When lead monoxide is added to dilute sulfuric acid, a thin layer of lead sulfate is formed on the surface of the solid lead monoxide. This layer protects the rest of the lead oxide from getting converted to lead sulfate in what is known as passivation.
To increase the amount of lead sulfate formed, the lead monoxide particles being added to the acid should be ground to a very fine powder. If the concentration of sulfuric acid is very high, a hydrated crystal of lead sulfate is formed that is soluble in the acid. This allows the formation of lead sulfate to continue without interruption.
An easier method of creating lead sulfate is with the reaction of lead nitrate and sulfuric acid. This works more efficiently as lead nitrate is soluble in water.