Mostly socket. Always check the motherboard manufacturers website for CPU compatibility list anyway.
Chipsets provide different function. Z77 for example provides overclocking for one. Whereas H67 and H61 and B75 does not. What CPU are you looking at? You should ask advice on your whole build.
It`s because while i`m searching for a CPU on the intel webpage they doesn`t seem to provide any information on the chipset. I can only find the chipset on the motherboard only. I`am just writing the PC specs for a Digital graphics designer.