Unknown alcohol sample. Chromic acid negative but iodoform positive?
I would recommend to repeat all the experiments one more time. The reasons for such results may be:


You had dirty test tube for ceric nitrate test, and it was really false positive. You could have a methyl ketone, which gives negative chromic acid test and positive iodoform test.
You added too much chromic acid, and had low amount of your "alcohol". That caused all alcohol to be oxidized, but that blue-green color was too faint, and you didn't notice it because of chromic acid excess.


Moreover, if your "alcohol" is immiscible with water, that means it is one of the higher alcohols. You could also try to identify it (if it's really an alcohol) by smell: those alcohols have pretty distinctive smells. x.x