An acid is termed weak or strong on the basis of it's disassociation constant (Ka). This is a function of it's chemical structure. Concentration is simply the number of molecules in a given volume.
Sulfuric acid has hydrophilic properties when concentrated, so it may have some effect on the reaction taking place. Oxalic acid is an reducing agent, so in titrations - which usually involve some...
Glacial acetic acid is a trivial name for water-free acetic acid, which is the more common name for (a solution of) ethanoic acid (CH3COOH). So in its most purest liquid state. Especially the food...