I had 3/4 pint of vodka for 6hours time frame on mon day then I took u.a test about 72-73 hours later. What is chance to pass the test?

Was this your FIRST test? Was it random? Ever fail a urine test?

That is skating on a line. The drug tests are supposed to find evidence of heavy drinking 60-80 hours afterwards. You're solidly in that time frame and I would consider 12oz of Vodka, ~6 standard drinks of 1.5oz, to be heavy drinking. This also depends on you and how your body reacts to alcohol and how long it takes for the metabolites to be removed from your system. I would give you 50/50 but I wouldn't bet ANY amount of money on it.

The more pertinent question is why you're being tested and, more importantly, what the consequences are if you fail? A lot of people who post questions exactly like yours are on probation, under watch by CPS, or employment agreement so they stand to lose their freedom, children, or job. Part of your life choices right now is to prioritize what's going on, drink or not. Good luck.