Final answer:
No, unconjugated bilirubin is not water soluble.
Step-by-step explanation:
Unconjugated (indirect) bilirubin is not water soluble. Bilirubin is a waste product formed in the liver when red blood cells are broken down. It needs to be converted into a water-soluble form to be excreted. In the liver, unconjugated bilirubin is conjugated with glucuronic acid to form bilirubin monoglucuronide and bilirubin diglucuronide, which are water-soluble and can be easily excreted in urine and feces.