PH PH In chemistry, pH () is a logarithmic scale used to specify the acidity or basicity of an aqueous solution. It is approximately the negative of the base 10 logarithm of the molar concentration, measured in units of moles per liter, of hydrogen ions. More precisely it is the negative of the base 10 logarithm of the activity of the hydrogen ion. At 25 °C, solutions with a pH less than 7 are acidic and solutions with a pH greater than 7 are basic. The neutral value of the pH depends on the temperature, being lower than 7 if the
Alkali Act 1863 Alkali Act 1863 Under the British Alkali Act 1863, an alkali inspector and four subinspectors were appointed to curb discharge into the air of muriatic acid gas (gaseous hydrochloric acid) from Leblanc alkali works. In 1874, under the Alkali Act 1874, the Inspector became the Chief Inspector. The first Chief Inspector was Dr Robert Angus Smith, he was statutorily responsible for the standards set and maintained by the Inspectorate, and reported directly to the Permanent Secretary of his department. For the first sixty years of its existence, the Inspectorate was solely concerned with the heavy chemicals industry, but from the