Qualitative filter paper is a fundamental laboratory consumable used for the rapid separation of solids from liquids. Unlike quantitative papers, which are used for gravimetric analysis, qualitative papers are designed for identifying materials and clarifying liquids where the weight of the remaining residue is not critical.
Fast Filtration (e.g., Grade 4): Best for coarse particles and gelatinous precipitates (e.g., ferric hydroxide). High flow rate but lower retention.
Medium Filtration (e.g., Grade 1): The "standard" lab paper. Ideal for routine applications and capturing medium-sized precipitates (e.g., lead sulfate).
