What is the cis or trans name for ch3brc=cclch3??

Expert Answers

An illustration of the letter 'A' in a speech bubbles

In naming this 4-carbon alkene first we have to locate the double bond. It is in the second carbon and therefore it is called 2-butene or but-2-ene. Next, we consider the substituent in the molecule. We can notice that there is a Br and a Cl attached to the second and third carbon. Alphabetically, Bromine should be named first and therefore the carbon where Br is attached is named as the Carbon 2; carbon 3 is not the carbon where Cl is attached. 

So we can partially name it as 2-bromo-3-chloro-but-2-ene. 

Now it is up to you whether it is a cis or a trans butene.

trans-2-bromo-3-chloro-but-2-ene

cis-2-bromo-3-chloro-but-2-ene

 

Approved by eNotes Editorial Team

Posted on

Soaring plane image

We’ll help your grades soar

Start your 48-hour free trial and unlock all the summaries, Q&A, and analyses you need to get better grades now.

  • 30,000+ book summaries
  • 20% study tools discount
  • Ad-free content
  • PDF downloads
  • 300,000+ answers
  • 5-star customer support
Start your 48-Hour Free Trial