Why Do Alkenes Turn Bromine Water Colourless?


Alkanes are saturated hydrocarbons, which does not decolourise the bromine water.

Which one will Decolourise bromine water?

Solution: Butyne, Ethene and Hexyne, all can decolourise bromine water.

Why does bromine water react with alkenes?

Alkenes react in the cold with pure liquid bromine, or with a solution of bromine in an organic solvent like tetrachloromethane. The double bond breaks, and a bromine atom becomes attached to each carbon. … (Fluorine reacts explosively with all hydrocarbons – including alkenes – to give carbon and hydrogen fluoride.)

Does Cyclobutane Decolourise bromine water?

It converts a yellow solution into a colourless solution. However, cycloalkanes do not decolourise bromine water because it consists of single carbon- carbon bonds which means that the molecule is saturated and it will show no reaction when cycloalkanes reacts with bromine water.

What happens when you add bromine water to hexane?

Alkane decolourisation of bromine water. … This is a substitution reaction, where one bromine atom replaces a hydrogen atom in the hexane, forming bromohexane (C6H13Br) and hydrogen bromide (HBr).

Does phenol Decolourise bromine water?

Hint: When bromine water is added to a solution of phenol in water, the bromine water is decolourised and a white precipitate is formed which smells of antiseptic. … We know that the reaction of phenol and water with bromine is known as bromination of phenol.

Can C5H10 Decolourise bromine water?

Compounds A, B and C all have the molecular formula C5H10. … Compound C is not an Alkene but is a cycloalkane as it does not decolourise bromine water. Compound A could be pent-1-ene, 2 methylbut-2-ene.

Which compound will Decolourise bromine water Fastest?

Answer: Alkene decolorizes bromine water so it is often used as a test for unsaturated hydrocarbon.

Why do alkanes not react with bromine water?

Alkanes do not react with spontaneously bromine water due to their saturated nature. Bromine is non-polar and therefore dissolves more readily in a non-polar alkane than in polar water. Therefore, when alkanes come into contact with bromine water, they cause it to decolourise, while they adopt the colour.

Do aldehydes Decolourise bromine water?

The answer is yes. Aldehydes will decolourise bromine water.

Does benzene Decolourise bromine water?

Benzene does not decolourise bromine water.

Is BR a bromine?

Bromine is a chemical element with the symbol Br and atomic number 35. It is the third-lightest halogen, and is a fuming red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour.

What happens to alkanes with bromine water is added?

Alkanes and alkenes tend to be colourless. So, when bromine water is added to an alkane or alkene and mixed well, initially the mixture turns a red-brown colour due to the bromine. … Alkanes are far less reactive than alkenes and will only react with bromine water in the presence of UV light.


Is bromine water safe?

Harmful if inhaled. Causes respiratory tract irritation and possible burns. Causes eye and skin irritation and possible burns. May cause digestive tract irritation with nausea, vomiting, and diarrhea.

What happens when phenol is reacted with bromine water?

If bromine water is added to a solution of phenol in water, the bromine water is decolorized and a white precipitate is formed which smells of antiseptic. The precipitate is 2,4,6-tribromophenol.

What happens when phenol is treated with excess of bromine?

Phenol is an organic compound that has an alcohol group attached to the benzene ring. Adding excess bromine water to the compound will result in Bromination and will give a white precipitate. … Therefore, the answer is – option (d) – When phenol is treated with excess bromine water, it gives 2,4,6-tribromophenol.

Why does phenol give Tribromophenol on bromination with bromine water?

Phenol reacts with bromine water to give 2,4,6-tribromophenol. … And Bromine ions are highly stabilized in ionic solvents.So the formation of strong o/p directing group and stabilization of Br+ enhances the formation of tribromophenol.

What happens when a few drops of bromine water are added to excess hex 1 Ene?

What happens when a few drops of bromine water are added to excess hex-1-ene and the mixture is shaken? … The colour of the bromine water disappears.

How does bromine water test for alkanes?

You can use bromine water, which is an orange solution, to distinguish between alkanes and alkenes. There is no change when bromine water is mixed with an alkane, but it turns colourless when mixed with an alkene.

Why does cyclohexane not react with bromine water?

Cyclohexane has no pi-unsaturation and is therefore not nucleophilic. It does not react with bromine unless energy in the form of light or heat is applied. In such a case a free-radical substitution reaction occurs. Cyclohexene is a typical alkene, and benzene and anisole are aromatic compounds.

Which compound will not Decolourise bromine water?

Bromine water is an orange solution of bromine. It becomes colourless when it is shaken with an alkene. Alkenes can decolourise bromine water, but alkanes cannot.

Can aromatic ring Decolourise bromine water?

Benzene doesn’t decolorize bromine water Bcoz benzene is an aromatic compound and if it undergoes anti addition with bromine it looses its aromaticity which is not possible.

Do carboxylic acids Decolourise bromine water?

It is both an Alkene and a Carboxylic acid. So it will decolourise Bromine water and also fizz when added to Carbonate solutions.

Leave a Reply

Your email address will not be published.