英语翻译In order to ensure the quality of products andmake nitro

英语翻译
In order to ensure the quality of products and
make nitrosation reaction complete,excessive sulfuric
acid and sodium nitrite are usually used to make the
starch-KI indicator blue in industrial production proc-
esses.The excess quantity of sulfuric acid and sodium
nitrite can not be avoided by the starch-KI indicator
method.It is important to accurately judge the end of
chemical reaction (3),to save raw materials such as
sulfuric acid and sodium nitrite and prevent the gen-
eration of nitric oxide toxic gases.
In this study,the end-point judgment method
based on starch-KI indicator is improved.In the ex-
periment,we first seal the system and connect U-tube
manometer to the flask,and then heat the system to
the reaction temperature and add sulfuric acid.As the
chemical reaction approaches the end,any changes on
manometer reading could be observed directly.When
the reading of the manometer increases continuously,
the end-point can be determined and the feeding is
stopped.In the industrial production,the system is
sealed as soon as feeding begins,the spring piezome-
ter is used to observe the change of system pressure
and determine the end of the reaction.