Examples of Acid and Base Based on Louis definition ​

An example is the reaction of ammonia with boron trifluoride. Figure 2. Ammonia and boron trifluoride. Boron trifluoride is the Lewis acid, while ammonia is again the Lewis base. As there is no hydrogen ion involved in this reaction, it qualifies as an acid-base reaction only under the Lewis definition.

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.