## Chemistry 12th Edition

First line: $[H^+]:$ $pH < 7$ $-log[H^+] < 7$ $log[H^+] > -7$ $[H^+] > 10^{-7}$ If the $pH$ is less than 7, at 25$^{\circ}$ C, the solution is acidic. Second line: $pH:$ $[H^+] < 10^{-7}$ $log[H^+] < log(10^{-7})$ $log[H^+] < -7$ $-log[H^+] > 7$ $pH > 7$ If the pH is higher than 7, the solution is basic. Third Line: Neutral solution: $pH = 7$ and $[H^+] = 10^{-7}$: Neutral: $[H^+] = [OH^-] = x$ $[H^+] * [OH^-] = 10^{-14}$ $x * x = 10^{-14}$ $x^2 = 10^{-14}$ $x = 10^{-7}$ $[H^+] = 10^{-7}$ Neutral: pH = pOH = y $pH + pOH = 14$ $y + y = 14$ $2y = 14$ $y = 7$ $pH = 7$