Please i tried to give this answer on a quiz but it was not accepted.

To name this alkane: CH3CH2CH2CHCH3 with a substituent of CH3 on 2nd carbon.

The compound is 2-methyl pentane

To name the given alkane (CH3CH2CH2CHCH3) with a substituent of CH3 on the second carbon, you need to follow a specific set of rules outlined by the International Union of Pure and Applied Chemistry (IUPAC). Here's how you can name it:

1. Start by finding the longest continuous carbon chain in the molecule. In this case, the longest chain consists of five carbon atoms, so it is a pentane (since "penta" means five).

CH3CH2CH2CHCH3
pentane

2. Number the carbon atoms in the longest chain consecutively, starting from the end closest to the substituent. In this case, the substituent (CH3) is on the second carbon from the left end of the chain.

CH3CH2CH2CHCH3
| | |
1 2 3

3. Indicate the location of the substituent by using the appropriate number and letter combination. In this case, since the substituent (CH3) is on the second carbon, we use the prefix "2-methyl" before the name of the main chain.

2-methylpentane

Therefore, the correct IUPAC name for the given alkane(CH3CH2CH2CHCH3) with a substituent of CH3 on the second carbon is "2-methylpentane."

If your answer was not accepted on the quiz, it is possible that the format or naming convention required by the quiz was different. It's always a good idea to double-check the specific guidelines provided by your instructor or the quiz question itself to ensure your response aligns with their requirements.