Answer the following question given this paragraph: 

electrolysis2NaOH ( aq ) + Cl2 ( g ) + H 2 ( g ) Bromine is much less abundant than fluorine or chlorine, but it is easily recovered from seawater, which contains about 65 mg of Br− per liter. Salt lakes and underground brines are even richer sources; for example, the Dead Sea contains 4 g of Br− per liter. Iodine is the least abundant of the nonradioactive halogens, and it is a relatively rare element. Because of its low electronegativity, iodine tends to occur in nature in an oxidized form. Hence most commercially important deposits of iodine, such as those in the Chilean desert, are iodate salts such as Ca(IO3)2. The production of iodine from such deposits therefore requires reduction rather than oxidation. The process is typically carried out in two steps: reduction of iodate to iodide with sodium hydrogen sulfite, followed by reaction of iodide with additional iodate: Equation 22.41.


Q: Bromine is much less abundant than fluorine or chlorine, but it is easily recovered from seawater, which contains about 65 mg of br− per what?


A:
liter