Technically, a vitriol itself was a metal sulfate salt, but 'vitriol' was often used as a shorthand for the acid and eventually has come to be applied to a cruel - or acidic - verbal attack. Mineral vitriols were known in ancient times, while oil of vitriol came into the alchemists' armoury around the thirteenth century. This was the classic example of a substance that was known and used long before it was entirely clear what it was.
However by the seventeenth century, sulfuric acid was being produced on a near industrial scale by burning a mixture of sulfur and saltpetre, or potassium nitrate, with steam to provide the hydrogen and extra oxygen to produce the acid.
The result is the familiar formula H 2 SO 4. One of the so-called bench acids, alongside hydrochloric and nitric, sulfuric acid is a very strong mineral acid - strong in the normal English sense because of its intensely corrosive nature, and strong in the chemical sense that it ionises completely in water when it loses its first proton to form a hydronium ion. Hydronium is the positive H 3 O ion, which forms in water rather than leaving a bare proton floating around.
Sulfuric acid is now made from sulfur dioxide in a catalytic process first devised in the s but the outcome is the same - a strong acid that is highly corrosive and that produces a considerable amount of heat when mixed with water. This is why acid must always be added to water rather than the other way around, to ensure that you don't get a small amount of water in a large amount of sulfuric acid, resulting in flash boiling and spattering with the corrosive fluid.
In this heat-producing reaction, the acid and water form sulfate and hydronium ions. Sulfuric acid is excellent at getting hold of water to react in this way. This is why concentrated sulfuric acid will turn paper black - it is extracting hydrogen and oxygen from the starch in the paper, leaving pure carbon.
Similar effects can be produced with other organic compounds - most dramatically with sugar, where an impressive tower of carbon is exuded. Sulfuric acid has a major industrial role in manufacturing fertilisers and detergents, where it is used to extract phosphate from rocks. It also finds its way into a plethora of industrial processes from removing corrosion from metals to making dyes. Most of us even own some sulfuric acid, though it is locked away where we rarely see it.
Car batteries have sulfuric acid at their heart in fact sulfuric is sometimes called battery acid. In the electrolytic reaction that powers the battery, lead and lead oxide electrodes are transformed to lead sulfate, resulting in an electrical charge flowing from plate to plate. Here on Earth, sulfuric acid tends not to hang around in the natural world. It is just too enthusiastic to combine with water, for example when falling as acid rain. This is rain in the form of dilute acid as a result of pollution - whether from chimneys or from the decomposition of natural materials.
Gases like sulfur dioxide and oxides of nitrogen combine with water vapour in the air to form dilute acids. Even 'clean' rain is acidic, as it reacts with carbon dioxide in the atmosphere to produce carbonic acid, but acid rain is significantly more corrosive, with a pH as low as 2.
One easy way that you can measure pH is with a strip of litmus paper. When you touch a strip of litmus paper to something, the paper changes color depending on whether the substance is acidic or basic. If the paper turns red, the substance is acidic, and if it turns blue, the substance is basic. How pH is Measured There are many high-tech devices that are used to measure pH in laboratories.
At this stage, the sulfur is burnt, converting it to sulfur dioxide. In the third stage, a catalyst known as vanadium V oxide on silica is used to convert sulfur dioxide to sulfur trioxide at K. Finally, the sulfur trioxide is converted to sulfuric acid by allowing it to react with water at a constant temperature of K. Structurally, a molecule of sulfuric acid , which has a molecular weight of Two of the oxygen atoms are double-bonded with the sulfur.
The other two atoms are single-bonded with sulfur but have hydrogen attachments. Because of valence shell electron pair repulsion VSEPR , a molecular model that predicts the geometry of the atoms, the oxygen atoms spread out in tetrahedral form.
This means that each oxygen is bonded at an angle of Just like other acids, the strength of sulfuric acid is measured by its acid dissociation constant in a solution. This constant, represented by the symbol Ka, does not change regardless of the concentration of the acid. The pH may change based on the concentration but not the Ka. The acid dissociation constant is also known as the chemical reaction equilibrium of acid with its base conjugate.
This is directly associated with the ratio between the formation of hydronium ions and the molecular acid. The larger the Ka, the stronger the acid as its ions dissociate more completely in a solution. Sulfuric acid has a Ka value of 1. This places the acid in higher rank compared to other acids.
In fact, sulfuric acid is one of the seven strong acids. The other strong acids are:. Although sulfuric acid is essential in many manufacturing processes, it is not commonly found in many products as the active constituent. A few products that contain the acid include:. Determining the pH value of any acid depends on various factors such as:. The pH or per hydronium value of a substance is measured on a logarithmic scale of 1 to This means that each value is the exponent of base ten.
Any neutral substance like pure water has a pH value of 7. Below 7 this is considered acidic, and above 7 is considered basic or alkaline.
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