Scientists use the $pH$ scale to represent the level of acidity or alkalinity of a liquid. This is based on the molar concentration of hydrogen ions, $[$H$+].$ Since the values of $H^{+}$vary over a large range, $1{10}^0$ mole per liter to $1{10}^{-14}$ mole per liter $(mo\frac{l}{L}),$ a logarithmic scale is used to compute $pH.$ The formula

$pH=-log[H^{+}]$

represents the $pH$ of a liquid as a function of its concentration of hydrogen ions, $H^{+}.$

The $pH$ scale ranges from $0$ to $14.$ Pure water is taken as neutral having a $pH$ of $7.$ A pH less than $7$ is acidic. A pH greater than $7$ is alkaline $($or basic$).$

For this exercise, use the formula for $pH.$ Round $pH$ values to $1$ decimal place.

a$)$ find pH for cola

b$)$ find pH for tomato juice

c$)$ which substance is more acidic