实验改进的思路棉线燃烧时之所以会产生“黄心”，有两个主要原因．其一，构成棉线的纤维素分子含有碳44．4％；燃烧时会产生“黄心”．其二，天然棉花在生长过程中会从土壤中吸收钙的无机盐，在棉线的精制过程中一般要用钠试剂，这两种盐也会产生“黄心”．我们先用盐酸，硝酸 The idea of ​​experimental improvement The reason why the cotton thread burns is “yellow heart”, there are two main reasons. For one, the cellulose molecules that make up the cotton contain 44.4% of carbon; when burned, it produces a “yellow heart”. Second, natural cotton absorbs inorganic salts of calcium from the soil during growth. In the refining process of cotton threads, sodium reagents are generally used. These two salts also produce “yellow heart”. We use hydrochloric acid first, nitric acid