Final answer:
Lead is not used for preparing hydrogen by treating it with dilute sulfuric acid because lead reacts too violently with sulfuric acid and forms lead sulfate, which is insoluble in water.
Step-by-step explanation:
The reason lead is not used for preparing hydrogen by treating it with dilute sulfuric acid is because lead reacts too violently with sulfuric acid.
When lead reacts with sulfuric acid, lead sulfate is formed, which is insoluble in water.