There are some major differencies between PIC16F72 and PIC16F73.
For example, 73 has USART, 72 doesn't, different program and data memories ..
In general, you can replace 72 with 73 but the other way around may be in some cases impossible.
As far as ADC is concerned, there is no difference between these two mcus ..
Regards,
IanP
U can Do that.
But I wonder why you want to go for 73 instead of 72.
Because f72 is very cheap as compared against f73.
If you are concerned abt memory then you can go for it.
ADC is same for the both.