Question

The IR spectrum of methanol (CH3OH) shows strong absorptions at 3340 (broad), 2945, 2833 and 1030 cm-1.
Which band is assigned to the O-H stretch?
Select one:
O A. 3340 cm-1
B. 2833 cm-1
O C. 2945 cm-1
0 D. 1030 cm-1​

Answer 1

Answer:

masses of involved atoms

F=force constant

From this equation, one can deduce some basic trends can be deducted:

a. If the force constant F (= bond strength) increases, the stretching frequency will increase as well (in cm-1)

Answer 2

The IR spectrum of methanol (CH3OH) shows strong absorptions at 3340 (broad), 2945, 2833 and 1030 cm-1.

And 3340 cm-1 is assigned to the O-H stretch

Hence correct answer is option (a)

Explanation:

The O-H stretch is usually a broad IR band. Which usually ranges between 3400-3200 cm-1.

This is the case if you run the IR spectrum of the pure liquid alcohol where the concentration is high.

And when we consider the other bonds, such as C-H bond, and Carbonyl compounds they gives rise to a weak bonds. Hence lower absorbtion ranges.