1. List the alcohol isomers of $C_4H_{10}O$

For molecular formula $C_4H_{10}O$, the alcohol isomers are:

• butan-1-ol
• butan-2-ol
• 2-methylpropan-1-ol
• 2-methylpropan-2-ol

The question asks for correct combinations of names for isomeric alcohols, i.e. two names referring to the same valid alcohol.

2. Check each option

Option A: tert-butanol and 2-methylpropan-2-ol

• tert-butanol is the common name of $(CH_3)_3COH$
• Its IUPAC name is 2-methylpropan-2-ol.

So, A is correct.

Option B: tert-butanol and 1,1-dimethylethan-1-ol

• tert-butanol is indeed $2$-methylpropan-$2$-ol.
• The name 1,1-dimethylethan-1-ol is not the correct IUPAC name.

Why?

Structure implied by this name would be equivalent to: $CH_3-C(OH)(CH_3)_2$ which simplifies to tert-butanol, but according to IUPAC rules we must choose the longest chain containing the $-OH$ group. That gives propan-2-ol as parent chain with a methyl substituent at carbon $2$: $2\text{-methylpropan-}2\text{-ol}$

Hence the given name is not acceptable here.

So, B is incorrect.

Option C: n-butanol and butan-1-ol

• n-butanol is the common name for the straight-chain primary butyl alcohol: $CH_3CH_2CH_2CH_2OH$
• Its IUPAC name is butan-1-ol.

So, C is correct.

Option D: iso-butyl alcohol and 2-methylpropan-1-ol

• iso-butyl alcohol has structure $(CH_3)_2CHCH_2OH$
• Its IUPAC name is 2-methylpropan-1-ol.

So, D is correct.

3. Final selection

The correct options are: $\boxed{A,\ C,\ D}$

4. Comparison with stored correct answer

Stored correct answer: A, C, D

My derived answer: A, C, D

They match.