A 220.0 mL sample of 0.20 M HF is titrated with 0.10 M NaOH. Determine the pH of the solution after the addition of 440.0 mL of NaOH. The Ka of HF is 3.5 × 10^ -4.

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:

i just learnt this recently but i need to look through my notes again