Benzene diazonium chloride is not stored and is used immediately after its preparation.

When aniline reacts with NaNO₂ + HCl at 273-278K, benzene diazonium chloride is formed. Thus product is highly unstable and therefore, is used immediately after its preparation. Benzene diazonium chloride is highly soluble in water at high temperature and is itself very stable at low temperature. Thus, benzene diazonium chloride cannot be stored for a long time.