Question

In the structure of testosterone, identify all the primary, secondary, tertiary, and quarternary carbons.

Answer 1

This refers to the number of carbons DIRECTLY attached to the carbon atom in question.

For example

Primary would have only one other carbon attached to it like ethane.

C-C: The first carbon has only ONE other carbon attached to it. Regardless of which carbon you look at here, they both have only ONE OTHER carbon attached.

Secondary would have 2 OTHER carbons attached to the carbon in question such as this Propane isomer.

C
|
C-C

The Centre Carbon has 2 other carbons attached to it, One above, and one to the right. making this a secondary carbon.

Tertiary Carbon would thus have 3 other carbon attached to itas this Isopropane. And Quartinary carbon would have 4 other carbons.

Tertiary: (the dots are there to just keep the structure in place for the answer application once submited)

....C
....|
H-C-C :
....|
....C

This proprane isomer shows that the centre carbon has 3 other carbons attached thus teritary.


And a Quartianry which you didnt ask for but ill explain anyhow:

.....C
......|
..C-C-C
.....|
.....C
The centre Carbon here has 4 other carbons attached to it.

If we substitute and superimpose numbers onto the quartinary example, as follows:

.....1
..2-3-4
.....5

Number 1 representing a carbon, would be primary
Number 2 would be priary as well as there is only ONE other Carbon attached to it or number in this case.
Number 4 & 5 would be like numbers 1 and 2 as well.
Number 3 would be Quartinary.


Now if we changed the structure to tertiary as follows( the placement of the numbers dont mean anything here):

....1-5
.....|
..3-2- 4

Then Number 1 is secondary b/c the numbers 5 and 2 are attached to it.
Number 2 is tertiary becasue it has 3 other numbers to it (3,4,1)
One numbers 5,3,4 are all primary bc they only have ONE carbon DIRECTLY attached to it.