Question

esculetin reacts with ____________ to produce the black color seen on this bea
6.5% nacl
cinnamaldehyde
ferric citrate
glucose

Explanation:

Esculetin reacts with ferric citrate to produce a black color. This reaction is a key characteristic in certain biochemical tests. 6.5% NaCl is a salt concentration used for other purposes like selecting for halotolerant bacteria. Cinnamaldehyde is an organic compound with different chemical properties and reactions. Glucose is a sugar and does not react with esculetin to form a black color in this context.

Answer:

ferric citrate