You can put this solution on YOUR website! "2 liters" only shows one significant figure. This "2 liters" can be anything from 1.9 liters to 2.1 liters. Actually to be more strictly correct, the 2 liters can be between 1.5 liters and 2.4 liters. Either of these bounds would be 2 to the nearest ONES place.
The biggest percent error would be between 2 and 1.5, which is a volume error of 0.5 liters.
Another important question, especially in practice, is "how well can the volume be read for measurement?"