Its bromo_ethane Ethane is C2H6 BUT we add one bromine in it , so it forms C2H5Br & one hydrogen is removes from the structure then it forms Bromo_ethane

The IUPAC name of CH3CH2Br is 1-bromopropane.

Explanation:

1. Identify the Longest Carbon Chain:
The first step in naming the compound is to identify the longest continuous carbon chain. In this case, we have a three-carbon chain, so it is known as propane.

2. Number the Carbon Chain:
Next, we need to number the carbon chain in such a way that the bromine (Br) atom gets the lowest possible number. In this case, the bromine atom is attached to the first carbon, so we number the chain from that end.

3. Indicate the Substituents:
Now, we need to indicate the substituents attached to the main carbon chain. Since we have a methyl group (CH3) attached to the second carbon, it is denoted as 2-methyl.

4. Name the Halogen Substituent:
The bromine atom is a halogen substituent, so it is named as bromo.

5. Combine the Names:
Finally, we combine all the names to get the complete IUPAC name of the compound. In this case, we have 2-methyl and bromo attached to propane. Therefore, the IUPAC name of CH3CH2Br is 1-bromopropane.

In summary, the IUPAC name of CH3CH2Br is 1-bromopropane. The name is derived by identifying the longest carbon chain, numbering the chain to give the bromine atom the lowest possible number, indicating the substituents (such as methyl) attached to the chain, and naming the halogen substituent (bromo) appropriately.