Question

You suspect an unknown compound possesses a disubstituted alkene. Select all pieces of spectroscopic information that must be present if your hypothesis is correct.

signals in the 13C NMR spectrum around 140 ppm
stretch in the IR spectrum at approximately 1650 cm-1
signals in the 13C NMR spectrum around 200 ppm
signals in the 1H NMR spectrum around 5.5 ppm
stretch in the IR spectrum at approximately 1700 cm-1
stretch in the IR spectrum at approximately 2200 cm-1
signals in the 1H NMR spectrum around 10.0 ppm
stretches in the IR spectrum immediately above 3000 cm-1
broad stretch in the IR spectrum at approximately 3500 cm-1

Answer 1

`\text{signals in the 1H NMR spectrum around 5.5 ppm}`

`\text{signals in the 13C NMR spectrum around 140 ppm}`

`\text{stretches in the IR spectrum immediately above 3000 cm-1}`

`\text{stretch in the IR spectrum at approximately 1650 cm-1}`

Step-by-step explanation:

The spectroscopy of distributed alkenes is adequately not the same as those of alkanes in many occurrences to make it conceivable to perceive when a double bond is available. For instance, in the infrared range of 1-butene, the assimilation band close to 1650cm−1 is normal for the extending vibration of the double bond.

As a rule, the power and position of this band rely upon the design of the alkene; it changes with the level of at the double bond, with the presence of a second unsaturated gathering in formation with the first, and with the evenness of the replacement of the double bond.

SO, from the information given: the correct information is:

`\text{signals in the 1H NMR spectrum around 5.5 ppm}`

`\text{signals in the 13C NMR spectrum around 140 ppm}`

`\text{stretches in the IR spectrum immediately above 3000 cm-1}`

`\text{stretch in the IR spectrum at approximately 1650 cm-1}`