<span>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 ONE's place.
The biggest percent error would be between 2 and 1.5, which is a volume error of 0.5 liters.
