Nhúng Thanh Zn Vào Dung Dịch Muối X, Sau Một Thời Gian Lấy Thanh ...

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Câu hỏi

Nhúng thanh Zn vào dung dịch muối X, sau một thời gian lấy thanh Zn ra thấy khối lượng thành Zn giảm. Lấy thanh Zn sau phản ứng ở trên cho vào dung dịch HCl dư, thấy còn một phần kim loại chưa tan. X là muối của kim loại nào sau đay?         

A.

A. Ni.

B.

B. Cu

C.

C. Fe

D.

D. Ag

Đáp án và lời giải Đáp án:B Lời giải:

Zn + dung dịch muối X → khối lượng thanh Zn giảm

Thanh Zn sau phản ứng + HCl dư → 1 phần kim loại chưa tan

Kim loại tạo muối X không phản ứng với HClLoại A và C.

+ Nếu x là Cu thì sau khi phản ứng với muối X khối lượng thanh kẽm giảm  gam (với x là số mol Zn phản ứng).

+ Nếu X là Ag thì sau phản ứng với muối X khối lượng thanh kẽm tăng gam (với x là số mol Zn phản ứng).

Vậy X là muối của Cu.  

Vậy đáp án đúng là B.  

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