The complexity of organic chemistry lies in the memorization and understanding of its general formulas. Hydrocarbons only contain carbon and hydrogen, and their structures can be chain-like or cyclic. Double bonds indicate alkenes, triple bonds indicate alkynes, while those connected by single bonds are alkanes. Aliphatic compounds form chain-like structures, while aromatic compounds have benzene rings. It should be noted that isomers have the same

After mixing concentrated nitric acid and concentrated sulfuric acid, it is necessary to cool them down before adding benzene dropwise to avoid nitric acid decomposition and benzene evaporation. The reaction is carried out in a water bath at 50-60℃. Excess nitric acid and sulfuric acid dissolve in water, while the yellow oily liquid that accumulates at the bottom of the beaker is nitrobenzene, which has a strong bitter almond odor. To prevent benzene evaporation, the test tube opening needs to be covered with a long glass conduit that functions as a condenser tube. In addition, sulfuric acid acts as both a catalyst and a dehydrating agent in this reaction.

According to recent reports, the Ministry of Foreign Affairs has issued a travel advisory stating that since the beginning of this year, Japan has experienced a decline in public safety, with a surge in criminal cases targeting Chinese citizens. There have been multiple incidents of Chinese citizens being attacked in Japan, and some cases remain unsolved. The security environment for Chinese citizens in Japan has continued to deteriorate. Recently, Japanese leaders have blatantly made explicit provocative remarks regarding Taiwan, severely worsening the atmosphere for personnel exchanges between China and Japan and posing significant risks to the personal and life safety of Chinese citizens in Japan.

Recently, Takashi Saiki made erroneous remarks regarding Taiwan, disregarding legal principles and historical facts. His series of words and deeds have endangered regional stability and harmed Japan itself. Japanese politicians and public opinion criticized Takashi, saying that as Prime Minister, he dragged Japan into a "national crisis" and bore "serious responsibility".