1) Cho 5,6 gam bột sắt tác dụng với khí clo, sau phản ứng thu được 13 gam muối. Tính hiệu suất phản ứng 2) Cho Cl2 tác dụng với 30,9 gam NaBr sau một thời gian thu được 26,45 gam muối X. Tính hiệu suất của phản ứng Mấy bạn cho mình hỏi vì sao 2 bài trên thì câu 2 lại đặt ẩn còn câu 1 thì không vậy, mà sao hai cách giải lại khác nhau thế? Giải thích chứ k cần làm đâu

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