PH of neutrality is not exactly 7 (25 °C), although this is a good approximation in most cases. Neutrality is defined as the condition where [H] = [OH] (or the activities are equal). Since self-ionization of water holds the product of these concentration [H]×[OH] = K, it can be seen that at neutrality [H] = [OH] = , or pH = pK/2. pK is approximately 14 but depends on ionic strength and temperature, and so the pH of neutrality does also. Pure water and a solution of NaCl in pure water are both neutral, since dissociation of water produces equal numbers
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