Which orbitals form a pi bond?

p  and d orbitals

Explanation:

A π bond forms when two orbitals overlap side-on.

The most common types are formed by the overlap of p orbitals (Fig. 1).

However, d orbitals can also overlap sideways with each other to form dπ-dπ bonds and with p orbitals to form dπ-pπ bonds (Fig.2).

in chemistry, a solution’s concentration is how much of a dissolvable substance, known as a solute, is mixed with another substance, called the solvent. the standard formula is c = m/v, where c is the concentration, m is the mass of the solute dissolved, and v is the total volume

particle   p is an electron and particle q is a neutron