Question: Explain the argument between Rebbe Akiva Aiger and the Ra”n on whether nullifying chometz within a majority of non-chometz is different from nullifying sheep wool in a majority of camel wool to combine it with linen and not transgress shaatnez?
A. The Teshuvas HaRan (64) says that chometz before the time of being forbidden to own is nullified in non-chometz even though it is permitted food being mixed with permitted food. It is just like a Mishna in Kilayim 9:1 which says that sheep wool and camel mixed together, if the majority is camel wool than it can be interwoven into linen and it is not shaatnez because only wool from a sheep is forbidden to be mixed with linen and camels aren’t sheep and the sheep wool is nullified to the majority of camel wool, even if it is permissible wool being mixed with permissible wool since the sheep wool isn’t intertwined with the linen yet.
B. Rebbe Akiva Aiger says the cases are incomparable because the sheep wool has a forbidden name to it to be mixed with linen so it can be nullified in the camel wool as if it is forbidden stuff being nullified in permitted stuff. Whereas chometz has no connection to prohibition whatsoever before the forbidden time on the eve of Passover.
C. What is the reason for prohibition?
Answer: Rebbe Akiva Aiger holds the reason for prohibition by chometz is time so that is why it is different from shaatnez but the Ra”n holds the reason for prohibition is the item i.e. the chometz it is just restricted by time meaning it is only prohibited on Pesach just like shaatnez where the reason for prohibition is the sheep wool but only when mixed with linen.