A kilometre is a unit of distance. A litre is a unit of capacity. The two units are therefore incompatible.
A liter is a cube exactly one tenth of a meter (1 decimeter) on a side. There are ten decimeters in a meter and so ten thousand of decimeters in a kilometer (1000 meters) There are exactly: 10 000 *...
The term liters per kilometer is the metric version of fuel economy; like miles per gallon in the United States.
That could depend on how fast you drive. Or it might not.
This is impossible to answer. A liter is a measure of volume; A kilometer is a measure of length. Length and volume measure different things.