Question

The Cis – 2 butene and Trans – 2 butene can be distinguished on the basis of:
1. Their optical properties
2. Their reduction products
3. The products of ozonolysis
4. Their addition product with bromine

Answer 1

Hint: First of all look at the properties of which they are talking about. Cis-2 butene and Trans -2 butene have same chemical properties but their physical properties are different. They both have different structures.

Complete Step by step answer: Let us go to each point one by one,
First is optical properties, so cis-2 butene and trans-2 butene have different physical properties but same optical properties.
Optical isomers are mirror images that are not super impossible. Your hands, assuming that we do not examine them too closely for scratches and other imperfections, are non superimposable images.
Now the next property is “reduction property”. So both have the same reduction properties as cis-2 butene and trans-2 butene have same chemical properties. Similarly they will give the same products after ozonolysis. So these three are the incorrect options.
Now the next one is an additional product with bromine. And in this case the products will be different as cis-2 butene gives two isomeric products and trans-2 butene gives products by following Markownikoff’s rule.

So the correct option is 4th.

Note: It is to be noted that cis-2 butene and trans-2 butene have different boiling and melting points. They also have different structures. One important thing to keep in mind is that there might be a presence of chiral centre bur even after that there may not be optical isomers.