Question

when a compound CH3 CH2 CH2 COOH

ITS IUPAC NAME IS BUTANIC ACID THIS WE KNOW ,BUT ITS STRUCTURE IS AS FOLLOWS:

C4-C3-C2-C1=O-OH

here why the numbers are written in a reverse order?

but in this compound

CH3CHCHCH2CH2CH3

IN THIS there are 6 c atoms they are no. as

c1 c2 c3 c4 c5 c6

here it is not reversed

this is why?

Answer 1

I don't understand the the structure of the carbon compound please keep the photo of the question