# find distribution diagram for acetic acid

# 1: provide equilibrium constants for all equilibrium reactions
Kw = 1.00e-14
Ka = 1.75e-5

# 2: provide total concentration for all mass balance equations
C = 0.1

# 3: set up master variable
pH = seq(1, 14, 0.0001)

# 4: calculate concentrations for all species in system
H3O = 10^-pH
OH = Kw/H3O
HA = C * H3O/(Ka + H3O)
A = C - HA

# 5: plot distribution diagram as function of concentration or as 
# function of log(conc)
plot(x = pH, y = HA, type = "l", col = "blue", lwd = 2, 
     xlab = "pH", ylab = "concentration of HA or A-", 
     main = "Distribution Diagram for Acetic Acid")
lines(x = pH, y = A, col = "red", lwd = 2)
legend(x = "right", legend = c("HA", "A-"), 
       lty = 1, lwd = 2, col = c("blue", "red"), bty = "n")
grid(col = "black")

plot(pH, log10(HA), type = "l", col = "blue", lwd = 2,
     xlab = "pH", ylab = "log(conc) of HA or A-", ylim = c(-10, 0),
     main = "Log Distribution Diagram for Acetic Acid")
lines(pH, log10(A), col = "red", lwd = 2)
lines(pH, log10(H3O), lwd = 0.25, col = "lightgray")
lines(pH, log10(OH), lwd = 0.25, col = "lightgray")
legend(x = "right", legend = c("HA", "A-"), 
       lty = 1, lwd = 2, col = c("blue", "red"), bty = "n")
grid(col = "black")