Organic Analysis

Question 1

What does an O–H bond in alcohols look like?

Answer 1

• Smooth curve in high range (3230-3550)

https://orgchemboulder.com/Spectroscopy/irtutor/alcoholsir.shtml

Question 2

What does an O–H bond in an acid look like?

Answer 2

• Wider + sometimes bumpier, overlaps with C–H bond (2500-3000)

https://www.chemguide.co.uk/analysis/ir/interpret.html

Question 3

When answering an IR question, what do you have to include? (2)

Answer 3

• Absorption range peak
• Type of bond

Question 4

What is the fingerprint region?

Answer 4

Region below 1500cm-1 ethic is unique to a particular compound

Question 5

How can IR spectrometry be used to confirm that compound is definitely ethyl butanoate?

Answer 5

Compare with known spectrum from a database, it should be an exact match

Question 6

Why can’t a mass spectrometer which measures m/z ratios to 1 decimal place tell the difference between C10H16O4 and C11H4O4?

Answer 6

They have the same molecular mass to 1 decimal place

Question 7

Why can’t high resolution mass spectrometer tell the difference between propan-1-ol and propan-2-ol?

Answer 7

They have the exact same molecular formula, so their molecular mass will be exactly identical

Question 8

Why does C have a relative molecular mass of 12.00000?

Answer 8

12C is a standard reference