“水玻璃与盐酸作用生成硅酸水凝胶”是大学一年级无机化学实验。若按现行教材所给实验步骤:“往2毫升20％水玻璃溶液里滴加6NHCl溶液,摇匀,若不生成凝胶,可微微加热。”实际上很难观察到有凝胶生成的现象。但是,如果将此实验改为:先加热20％Na_2SiO_3至沸,再沿试管壁滴加6NHCl,则迅速生成了硅酸水凝胶,现象颇为明显。 “Water glass and hydrochloric acid generated silicate hydrogel” is a freshman university inorganic chemistry experiment. According to the current teaching materials to the experimental steps: “To 2 ml of 20% water glass solution was added dropwise 6NHCl solution, shake, if not generate gel, can be slightly heated.” In fact it is difficult to observe the phenomenon of gel formation . However, if the experiment was changed to: first heating 20% ​​Na_2SiO_3 to boiling, and then dropping along the tube wall 6NHCl, the rapid generation of silicate hydrogel, the phenomenon is quite obvious.