Write the IUPAC name for the following compound: $C_2{H}_5-\mathrm{CH}\left(\mathrm{CH}{3}_{}\right)-\mathrm{CH}\left(\mathrm{Cl}\right)-\mathrm{CH}{2}_{}-\mathrm{CH}{3}_{}$

• A. $3-\mathrm{chloro}-3-\mathrm{methyl}\mathrm{pentane}$
• B. $3-\mathrm{chloro}-2-\mathrm{methyl}\mathrm{pentane}$
• C. $2-\mathrm{chloro}-2-\mathrm{methyl}\mathrm{pentane}$
• D. $2-\mathrm{chloro}-3-\mathrm{methyl}\mathrm{pentane}$

Answer: (A)

Verified step by step guidance

1. Identify the longest continuous carbon chain in the molecule. This chain determines the base name of the compound (e.g., pentane for a 5-carbon chain).
2. Number the carbon chain from the end nearest to the first substituent (either a methyl group or a chlorine atom) to give the substituents the lowest possible numbers.
3. Locate and name the substituents attached to the main chain. In this case, identify the positions of the methyl group (CH3) and the chlorine (Cl) atom on the carbon chain.
4. Assign numbers to each substituent based on their position on the chain, and list them alphabetically in the name regardless of their position numbers.
5. Combine the substituent names and numbers with the base name of the alkane to write the full IUPAC name, using hyphens to separate numbers and words, and commas to separate multiple numbers.