4.5L of 0.5% ABV beer would not make you drunk. For comparison, this is equivalent to less than a pint of a typical mainstream beer. Indeed a 0.5% ABV drink can be branded alcohol free (at least in the UK).
Would 4.5L of 2% ABV make you drunk? Depends how quickly you can drink it. It's 9 units of alcohol. We commonly assume the body can process 1 unit/hour so if this quantity was consumed over an entire day, I don't think you'd get merry.
I'm not saying it's a good idea to drink like this, just highlighting the impact of ABV on the outcome.
Would 4.5L of 2% ABV make you drunk? Depends how quickly you can drink it. It's 9 units of alcohol. We commonly assume the body can process 1 unit/hour so if this quantity was consumed over an entire day, I don't think you'd get merry.
I'm not saying it's a good idea to drink like this, just highlighting the impact of ABV on the outcome.