PH temperature increases. Pure water is neutral, pH 7 at (25 °C), being neither an acid nor a base. Contrary to popular belief, the pH value can be less than 0 or greater than 14 for very strong acids and bases respectively. Measurements of pH are important in agronomy, medicine, chemistry, water treatment, and many other applications. The pH scale is traceable to a set of standard solutions whose pH is established by international agreement. Primary pH standard values are determined using a concentration cell with transference, by measuring the potential difference between a hydrogen electrode and a standard electrode such
Alkali manufacture Alkali manufacture Alkali manufacture is the process by which an alkali is made. Typical alkalis, produced commercially, include sodium hydroxide, sodium carbonate, potassium hydroxide and potassium carbonate. A number of processes have been proposed for the manufacture of alkali from various metals, the most common being the Leblanc and ammonia-soda processes. The Leblanc process, which was invented by Nicolas Leblanc around 1790, begins with the decomposition of sodium chloride by sulfuric acid, by which sodium sulfate and hydrochloric acid are produced. The sodium sulfate is afterwards fired with calcium carbonate and coal. Sodium carbonate can be extracted from this mixture