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部分試題

Floor 1 HSbF6Onizuka 7/28/12 7:02
(2006•蘭州)選用下列試劑中的一種,就能鑑別鹽酸、澄清石灰水、食鹽水三種無色溶液,這種試劑是(  )

A.燒鹼溶液 B.硫酸銅溶液C.無色酚酞試液 D.氯化鈣試液

解:A、將燒鹼滴入三種溶液中,和澄清石灰水、食鹽水不反應,雖然和鹽酸反應,但生成的是水,也沒明顯現象,不能鑑別,故A錯誤,B、將硫酸銅加入三種溶液中,出現藍色沉澱的是氫氧化鈣,沒有現象的是鹽酸和食鹽水,然後應將剩餘的兩種液體滴入藍色沉澱中,沉澱溶解的是鹽酸,沉澱不變的是食鹽水,故B正確,C、無色的酚酞遇到鹽酸和食鹽水都不變色,現象相同,不能鑑別,故C錯誤,D、氯化鈣和三種溶液都不反應,都沒有現象,不能鑑別,故D錯誤,故選B.

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