Which of the following substances would decolourise bromine? .

Question

BlackTom AI · Accepted Answer

The question asks which substance would decolourise bromine. This is a classic test for unsaturation in organic compounds.
First, consider the mechanism: bromine water is orange/brown in colour, and it fades to colourless when an alkene (a compound with a C=C double bond) undergoes an addition reaction with Br2, forming a vicinal dibromo compound. This happens because the electrons in the carbon–carbon double bond polarise Br2 and lead to a rapid electrophilic addition, consuming Br2 and removing its colour.
Now apply this to the provided answer note: 'd. ethene' is listed as the correct option. Ethene (C2H4) contains a C=C double bond, so it readily reacts with bromine water to form 1,2-dibromoethane, decolourising the solution. This aligns with the standard observation that alkenes decolourise bromine.
What would be the expected explanation for the other potential substances (if they were present as options)? In general:
- Alkanes (no C=C) do not react with bromine under mild conditions; bromine water remains orange/brown, so no decolourisation occurs.
- Alkynes (C≡C) can also decolourise bromine, though under different conditions (and often more rapidly) due to their higher unsaturation.
- Benzene rings (aromatics) typically resist bromine decolourisation in the absence of a catalyst or high-energy conditions; they require radical halogenation conditions to show noticeable decolourisation.
- Halogens or other oxidising agents may oxidise or react with bromine differently, but they do not simply mimic the alkene test.
In summary, the statement that ethene would decolourise bromine fits the well-established test for unsaturation through electrophilic addition to a C=C bond, producing a colourless product as Br2 is consumed.

Which of the following substances would decolourise bromine? .

查看解析

登录即可查看完整答案

类似问题

Which of the following statements is true regarding the chemicals that are used in this experiment?

Which of the following substances would decolourise bromine? .

What is the minimum number of carbon atoms required for a hydrocarbon to be classified as an alkene?

Q12 V3A compound underwent two tests.In the first test, 1 mole of the compound was completely combusted, yielding 3 moles of CO2.In the second test, the compound showed a rapid reaction with bromine. The formula of the compound is likely to be:

In a consumer society, many adults channel creativity into buying things

Economic stress and unpredictable times have resulted in a booming industry for self-help products

People born without creativity never can develop it

A product has a selling price of $20, a contribution margin ratio of 40% and fixed cost of $120,000. To make a profit of $30,000. The number of units that must be sold is: Type the number without $ and a comma. Eg: 20000

更多留学生实用工具

考试浏览器助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单