Hydronium and hydroxide ions are present in all aqueous solutions. Solutions are neutral if [H3O+] = [OH−]. At 25°C, Kw = [H3O+][OH−] = 14.00. pH = -log[H3O+], pOH = -log[OH−]
NaOH is a corrosive solid soluble in water. NaOH completely dissolves in water to release hydroxide ions. NaOH has pH value around 12, making it a strong base
pH measures acidity or alkalinity of chemical solutions. pH scale ranges from 0 to 14, with 7 being neutral. pH = -log[H+] where [H+] is hydrogen ion concentration