2.5 liter equals how many quarts?

no. U.S. gallons are different from imperial gallons. 1 Imperial gallon is equal to 4.54609188 litres and 1 US gallon is equal to 3.78541178 litres. Liters on the other hand are the same everywhere. One liter equals 0.26 U.S. gallon or 0.219 Imperial gallon.