Statement I: Cross aldol condensation between two different aldehydes produces four products only if both aldehydes have -hydrogen atoms. If one aldehyde lacks -hydrogen (e.g., benzaldehyde and acetaldehyde), only two products are typically formed (one self and one cross). If neither has -hydrogen, no aldol condensation occurs. Thus, it does not 'always' produce four products. Statement I is false.

Statement II: Benzaldehyde is an aldehyde and acetophenone is a ketone. Aldehydes are generally more reactive than ketones towards nucleophilic addition reactions due to less steric hindrance and greater electronic deficiency of the carbonyl carbon. Therefore, semicarbazide will react faster with benzaldehyde than with acetophenone. The statement claiming it forms a product with acetophenone only is incorrect. Statement II is false.