Is it permissible to give Zakat on gold to someone who wants to marry, or to spend it on Da‘wah, such as buying tapes and booklets and distributing them?

It is not permissible to pay Zakat (definition) to anyone other than the eight categories specified by Allah the Almighty in Surat At-Tawbah (definition): (إِنَّمَا الصَّدَقَاتُ لِلْفُقَرَاءِ وَالْمَسَاكِينِ وَالْعَامِلِينَ عَلَيْهَا وَالْمُؤَلَّفَةِ قُلُوبُهُمْ وَفِي الرِّقَابِ وَالْغَارِمِينَ وَفِي سَبِيلِ اللَّهِ وَابْنِ السَّبِيلِ فَرِيضَةً مِنَ اللَّهِ وَاللَّهُ عَلِيمٌ حَكِيمٌ) "Zakat expenditures are only for the poor and for the needy and for those employed to collect [Zakat] and for bringing hearts together [for Islam] and for freeing captives [or slaves] and for those in debt and for the cause of Allah and for the [stranded] traveler - an obligation [imposed] by Allah. And Allah is Knowing and Wise." The word "Innama" (إِنَّمَا) denotes exclusivity. What some scholars have mentioned regarding this falling under the category of "fi sabilillah" (in the cause of Allah) is incorrect. The correct view is to restrict Zakat to the categories mentioned in the verse.