How many times more acidic is pH2 than pH4?

100 times more acidic.

Explanation:

If you look at the pH scale, pH2 is 2 "jumps" away from pH4, therefore, pH2 is 100x more acidic than pH4.

in cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. a contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.

explanation:

because of all the things that happen around the us, many people get into arguments which sadly could get physical, but we should actually make a change for that.