system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
The molecule, which is the initiator of cataract formation in the eye lens and whose 1-phosphate derivative is responsible for the liver failure, is
assistant
The correct answer is  Galactitol

Galactitol and sorbitol both can cause cataract.
But there is one more information in the question, i.e. 1-phosphate of that metabolic is responsible for the liver failure. Galactose-1-phosphate cause liver failure in galactosemia.
So, the examiner is asking about cataract in galactose