The chemical pretreatment processes were compared based on their brief descriptions, followed by the advantages and disadvantages of each process. Process complexity and reliability differ; consequently, their potential for creating higher sugar yields are different in such a way that introducing the best pretreatment method is not possible. These processes focus on lignin removal and in enhancing the enzymatic degradability of cellulose. Acid pretreatment particularly enhances the hydrolysis of hemicellulose to sugars. For the limitations considered for each chemical method, any treatment that requires lower-cost chemical reagents and conditions and yields more sugar is preferable.