how does magnetic moment related to unpaired electrons in transition metals? arrange the following acids in their increasing order of acidic strength. acetic acid, chloro acetic acid, propanoic acid, formic acid. how does acetic acid reacts with PCl5?
Answers
i)Magnetic moment = √n(n+1)
so if there are unpaired electrons then there will be some magnetic moment. As in transition element there are unpaired electrons in d orbital which provides them paramagnetic property.
ii) acidic acid strength :- propanoic acid < acetic acid < formic acid < chloroacetic acid
In it the main concept is the halogen containing carboxylic acid is always more acidic then the one having hydrocarbon chain like Ch3 in acetic acid (Ch3COOH), C2H5 in propanoic acid(C2H5COOH)
As halogen is electron withdrawing group means it will attract electron towards itself and will decrease the electron density on COOH, hence it will act as a proton donor i.e. it will easily give H+ from carboxylic group so it will have more acidic strength. Now, the Alkyl group i.e. Ch3 etc is electron repelling group so it will push it's electron towards COOH this will increase the electron density on it and will not easily loose the proton. So the more number of these hydrocarbon as in the given example propanoic will have more Hydrocarbon so it will be the weakest acid.
iii) acetic acid + PCl5 ---> acetyl chloride
In this the COOH group will be converted to COCl and on OH- will be removed.
Hope it will help you to clear the reason of the answer. ヾ(＾-＾)ノ