Explanation:

Paper production is basically a two-step process in which a fibrous raw material is first converted into pulp, and then the pulp is converted into paper. The harvested wood is first processed so that the fibres are separated from the unusable fraction of the wood, the lignin. Pulp making can be done mechanically or chemically. In the chemical pulping process, alkali (e.g., sodium hydroxide in the form of a lye or caustic soda) is usually used to remove the lignin that binds the fibres. So, for degumming of raw material, caustic soda is used.