sodium borohydride (NaBH4) is used industrially in many organic syntheses. one way to prepare it is by reacting sodium hydride with gaseous diborone. Assuming an 86.8% yield,how many grams of NaBH4 can be prepared by reacting 7.98g of sodium hydride and 8.16g of diborone?

i tried 9.68 but it didn't work