Take two type C2 chambers (containing petroleum ether as eluent) UNDER THE HOOD.

On two long TLC plates, make a deposit of ferrocene in petroleum ether (vial 11), equidistant from the bottom of the plate (locate the deposit by marking it with a pencil).

Elute each plate in each of the chambers, while at the same time:

• closing the first chamber (C2a) during elution
• leaving the second chamber (C2b) open during elution.

Wait until the solvent front of the TLC in chamber C2a is high. Stop both TLCs and indicate the solvent migration front.

Calculate the Rf values. Conclude.