Question

Reduction of silver nitrate by sodium borohydride equation

Answer 1

The formation of silver nanoparticles can be observed by a change in color since small nanoparticles of silver are yellow. A layer of absorbed borohydride anions on the surface of the nanoparticles keep the nanoparticles separated. When sodium cholride (NaCl) is added the nanoparticles aggregate and the suspension turns cloudy gray. The addition of a small amount of polyvinyl pyrrolidone will prevent aggregation.