Growing a silver tree requires only a few hours.
Scientific
name: Mercury displaces silver from silver nitrate.
Safety
Wear eye protection goggles and gloves. Mercury is highly toxic. Perform this experiment in a fume hood.
Always follow general safety
recommendations. Please note that conducting chemistry
experiments you must comply with the relevant legal procedures in
your country.
Scientific background
The reaction of mercury and silver nitrate is an example of a single displacement reaction. Mercury displaces silver from silver nitrate. Silver moves out of the compound. The reaction is possible due to the difference in activity between the metals. A metal’s activity can be estimated from its position in the reactivity series. In the reactivity series metals are arranged from most active to least active. The row looks as follows: Li, K, Sr, Na, Ca, Mg, Al, Zn, Cr, Fe, Cd, Co, Ni, Sn, Pb, H, Sb, As, Bi, Cu, Hg, Ag, Pd, Pt, Au. Mercury is more electropositive than silver and is able to displace it. The reaction under study is also a oxidation-reduction chemical reaction. Mercury is reduced and changes its oxidation state from 0 to + 1. Silver is oxidized and changes its oxidation state from + 1 to 0. This means that mercury donates its electrons to silver. The silver produced on the surface of the mercury drop forms an amalgam with mercury – an alloy which consists of both metals. The anisotropy of surface energy defines the favorable directions of crystal grow. The system tries to minimize surface area with high energy which results in formation of tree-like structure