Can u please give a small concept of eudiometry

Can u please give a small concept of eudiometry. The basic formulas and how to solve its question with some examples.

udiometry are calculations based on gaseous reactants. it is mainly based on avogadros law which state that equal volumes of all the gases under similar conditions of temperature and pressure contains equal number of molecules.
eg. A(g) + B(g) → C(g) + D(g)
a volumes b volumes c volumes d volumes
a moles b moles c moles d moles
in the following problems we shall again see that the balancing gaseous reactions are not required if solved by POAC method.