I have bad breath. is that why my tongue is white?

Oral hygiene: Most bad breath is due to decaying crud in the mouth, between the teeth or on the tongue. The white stuff on your tongue is probably the cause of the odor. A good dental flossing with running it over the back of the tongue cures most of these. If it does not, look for a problem in the upper aerodigestive system.

Bad breath: Bad breath can be from a host of both dental and medical conditions. By far the biggest cause is poor oral hygiene which results in decaying food debris between teeth, under gums and on tongue. The white tongue can be merely plaque or any one of a number of other conditions. See your dentist to get a proper diagnosis, counselling and treatment. You can't solve this on your own over the internet.