“Tin dendrite” experiment

How to grow a metal dendrite using electricity

A sim­i­lar ex­per­i­ment is in­clud­ed in the “Tin” set from the MEL Chem­istry sub­scrip­tion

Safe­ty pre­cau­tions

Wear pro­tec­tive gloves and glass­es

Reagents and equip­ment:

  • tin(II) chlo­ride (10 g);
  • wa­ter (30 ml);
  • 70% acetic acid (10 ml);
  • three Petri dish­es;
  • two clips with­out wires;
  • two clips with wires;
  • elec­tric­i­ty source with di­rect cur­rent;
  • beaker.

Step-by-step in­struc­tions

In the beaker, dis­solve tin(II) chlo­ride, then add acetic acid. Con­nect three Petri dish­es with the clips, and pour the pre­pared so­lu­tion into each dish so that it will make con­tact with the clips. Con­nect one end of the clip with wires to the dish­es on the side, and the oth­er to the elec­tric­i­ty source. Watch the tin den­drite start to grow. If the po­lar­i­ty is changed, the den­drite will start to grow in the op­po­site di­rec­tion.

Pro­cess­es de­scrip­tion

When a di­rect elec­tric cur­rent is passed through a tin(II) chlo­ride so­lu­tion, elec­trol­y­sis takes place. On the neg­a­tive elec­trode (cath­ode), tin(II) ions are re­duced to met­al in the form of crys­tals re­sem­bling frag­ile tree branch­es.

Sn²⁺ + 2e⁻ = Sn⁰(met­al)