Question

Carry out a Hammett correlation for the reaction of substituted benzoic acids with diazophenylamine . in ethanol if the following data was collected at 303 K³

Substituent	p-CH3	m-CH3	H	m-OCH3	p-Cl	p-Br	m-Br	m-NO2	p-NO2
log (k/ko)	-1.01	-0.650	0.0	1.14	1.77	1.98	4.31	8.32	8.82
s (sigma sign)	-0.19	-0.09	0	0.19	0.59	0.79	1.09	2.08	2.37

Determine the reaction parameter, r, for this system. b) Is this reaction enhanced (faster) if the reaction site is electron rich or electron poor? Explain your answer. d) Which substituent in the table above yields the fastest reaction? Explain your answer.

Answer 1

Solution:

a) from the above graph r factor can be found from the trendline.

b) Yes the reaction gets faster by addition of electron rich and vice versa for the slower process

d) para-NO2 as its having positive value and gives the maximium substituents by enhancing faster reaction through favoured para position.