if he khula's her for a slave that she has not specified, and it turns out to be free, or usurped property, or for vinegar and it turns out to be wine, the khula' is valid according to the view of the majority of scholars. This is because khula' is a compensation (mu'awadah) for the private parts (bud'), so it is not invalidated by the invalidity of the compensation, just like marriage. However, he may demand from her its value as if it were a slave. Abu Thawr and the two companions of Abu Hanifa have stated this. If he khula's her for this specific vessel of vinegar, and it turns out to be wine, he may claim from her its equivalent in vinegar, because vinegar is among those things with equivalents (dhawat al-amthal), and he entered into the contract on the basis that this specific object was vinegar, so he is entitled to its equivalent, just as if it were vinegar and it perished before he took possession of it. It has been said: He may claim the value of its equivalent in vinegar, because wine is not among those things with equivalents. The correct view is the first one; for she was only obligated to provide its equivalent if it were vinegar, just as the value of a free person is required by presuming him to be a slave, even though a free person has no [monetary] value. Abu Hanifa said regarding the entire issue: He returns to the named compensation. Al-Shafi'i said: He is entitled to the dowry of a similar woman (mahr al-mithl), because it is a contract for the private parts with an invalid compensation, thus resembling marriage with wine. Abu Hanifa argued that the departure of the private parts has no [monetary] value, so if he was deceived (ghurra bihi) by it, he may reclaim from her what she took. Our position is that it is a physical entity (ayn) that must be delivered upon its soundness and the remaining reason for entitlement, so its substitute must be determined by its value or its equivalent, like usurped or borrowed property. If he khula's her for a slave and it turns out to be usurped or an umm al-walad (a slave mother), Abu Hanifa concedes this and agrees with us on it.

Section: If he khula's her for something prohibited, while both know of its prohibition, such as a free person, wine, pork, or carrion, it is exactly like a khula' without compensation; he is entitled to nothing. Malik and Abu Hanifa held this view. Al-Shafi'i said: He is entitled to the dowry of a similar woman from her; because it is a compensation for the private parts, and if the compensation is prohibited, the dowry of a similar woman becomes mandatory, as in marriage. Our position is that the departure of the private parts from the husband's ownership is not a valuation-based transaction (ghayr mutaqawwam), as we have previously mentioned. Thus, if he is satisfied with no compensation, he is entitled to nothing, just as if he had divorced her or suspended her divorce upon the doing of something, and she did it. It differs from marriage; for the entry of the private parts into the husband's ownership