- #1

AMan24

- 58

- 2

## Homework Statement

Lets say i have C

_{5}H

_{10}O.. The IHD is (5x2+2-10)/2 = 1 IHD

So now i use my IR chart and i determine i have ketone

Now i want to find the new IHD and also figure out what other atoms i have left. So i need to subtract C

_{5}H

_{10}O by ketone and figure out the new IHD.

## Homework Equations

Given formula: C

_{c}H

_{h}N

_{n}O

_{o}X

_{x}

IHD = 0.5 * [2c+2-h-x+n]

3. The Attempt at a Solution

3. The Attempt at a Solution

So for ketone, my guess would be either subtracting CO from the original formula or subtracting C

_{2}H

_{3}O then calculating the new IHD which would be either

C

_{5}H

_{10}O - C

_{2}H

_{3}O = IHD 0.5 which doesn't make sense

C

_{5}H

_{10}O - CO = IHD 0, which

*does*make sense, but is it correct

And you might say i don't need to calculate it for this problem, but i just want to know for in the future because for some problems finding the new IHD is useful...

**My question is: What am i supposed to subtract exactly? And not just for this example but, let's say i have aldehyde, do i just subtract the CO or do i subtract CHO**