Bromine Test

Before we get to the details of bromine test, let's take a quick refresher of what bromine is and what are the properties of this chemical element. Bromine belongs to the halogen group of chemical elements in the periodic table. Its atomic number is 35 and it possesses an atomic mass of 79.904. Although it is a relatively rare element in the Earth's crust, the fact that it is highly soluble causes bromine ions to be present in oceans and naturally occurring saline water bodies. Owing to this reason, it can be easily extracted from saltwater pools and other brine water sources for commercial utility. Appearance wise, elemental bromine exists as a dense, translucent, mobile, reddish-brown liquid which readily transforms into a reddish-brown vapor when exposed to standard temperature and pressure.

Although a non metallic element, bromine may assume metallic properties when a 55 GPa pressure is applied to it. As a chemical, bromine reacts actively with metals. In case water is also present at the time of such reaction, bromine reacts with metals to produce bromine salts. Bromine has the ability to easily form bonds with many other elements. It also possesses bleaching properties. Now that we are in the flow, let's get to know the details of bromine test. I suggest you read about bromine uses if you're wondering what this element is used for.

What is a Bromine Test?

Bromine test is used to detect the presence of unsaturated compounds alkene and alkyne. Such a test for alkenes work via the mechanism of making alkenes or hydrocarbons having a minimum of one double bond undergo addition reactions. A bromine test for unsaturation makes the alkenes and the aforementioned hydrocarbons combine with the bromine to impart a colorless appearance to the otherwise reddish-brown bromine. The equation for such a reaction is symbolically depicted as follows:

H₂ = CH₂ ---> H₂BrC - CbrH₂

For those who are wondering what an addition reaction is, it is the phenomenon where a smaller molecule adds on across a double bond. Since alkenes contain double bonds, they are capable of undergoing addition reactions. As for the change in bromine's color, alkenes are colorless and therefore, their combination with bromine causes the latter to lose color as well as it gets consumed in the process of reaction. A bromine test is also conducted to detect the presence of phenolic compounds like phenol, cresol, etc. A bromine water test is one of the best, easiest and surest ways to detect the presence of unsaturated double bond compounds and phenols in any unknown sample. The presence of phenols, however, can be identified differently from the presence of alkenes and unsaturated double bonds as when phenols come in contact with bromine solutions, the resultant precipitate is white in color.

What are Bromine Test Strips?

These strips are commercially available strips of bromine coated material which are used to test the alkalinity, hardness and pH of swimming pool and spa waters. These tests are essential to detect undesirable chemical elements in water in order to maintain water quality. This is true especially in case of beauty and wellness spas that run therapeutic baths and any imbalance in the chemical composition of such bath water may be detrimental to the client's wellness and beauty regime. Some well-known bromine test strip brands that market bromine strips to test swimming pool and spa water for alkalinity and hardness are as follows:

• Leisure Time Spa Bromine Test Strips
• Advantis Technologies Leisuretime Bromine Test Strips
• Aquacheck 3 Way Bromine Test Strips
• Aquacheck Red "bromine" Pool Spa Test Strips
• Tru-Blu Sodium Bromide Test Strips

That, I presume, should clarify what a bromine test is all about and why it is conducted. Most common instances of bromine test include its performance in laboratories, as part of chemistry practicals and for testing water quality of swimming pools and spas. Bromine test is a qualitative test, as you must have concluded by now.