Which of the following molecules has a characteristic broad stretch at 3300 cm-1? A) (CH3)2CHCH2OH
B) (CH3)3CH
C) (CH3)2CHCCCH3
D) (CH3)2CHCH=CH2
E) (CH3)2CHCO2CH3

The answer is "Option A"

Explanation:

At 3300 cm-1, the wide region is equal to OH. It is a possible group of alcoholic features that includes drugs. In the given choices option a is correct that's the structure can be defined in attachment file please find it, and the wrong choice can be defined as follows:

In choice B, It is wrong because it doesn't include OH.  In choice C, it uses the triple bond, that's why it is wrong. In choice D, it uses the two bonds, that's why it is wrong. In choice E, it uses the characteristic bond, that's why it is wrong.

Bthats what im doing to and i figured it out it is b

Ithink about 50 % of an original isotope's number of atoms remain