When water is placed in a buret it forms a concave meniscus at the surface. In contrast, mercury (in a manometer for example) forms a convex meniscus (Figure 11.17). Explain why this phenomenon occurs, and why the two liquids give different results. Predict the meniscus shape if the buret is filled with ethylene glycol (HOCH₂CH₂OH).

Data given in Figure 11.17

Transcribed Image Text:

Capillary Action A piece of paper is partly immersed in water. Polar water molecules are attracted to the C-OH groups in the cellulose of the paper and water moves up the paper. Figure 11.17 Intermolecular forces: capillary action (left) and the formation of a meniscus (right). Meniscus Water in glass tubes (right) is attracted to the polar -OH groups on the surface of glass and so water forms a downward facing or concave meniscus. Mercury, however, is not attracted to the glass surface, and so forms a convex meniscus (left). ⒸCengage Learning/Charles D. Winters