關於Detection of substances的化學問題

Tieria

2010-01-23 5:33 am

1. A student collected samples of two minerals – X and Y. Both minerals are colourless and crystalline, though Y is obviously mixed with small amounts of a reddish brown solid. X is insoluble in water while Y is almost completely soluble. The following table shows the results of tests conducted on X and Y.

Test

Description

Observations

I

Flame test

X gave a dull red flame colour.
Y gave a yellow flame colour.

II

X was added to dilute hydrochloric acid

X dissolved in dilute hydrochloric acid with the evolution of a gas that turned limewater milky.

III

Dilute nitric acid was added to a solution of Y, followed by silver nitrate solution

A white precipitate formed.

a) The reddish brown solid mixed with Y is insoluble in water. Suggest how you would show that it contains iron(III) ion.

回答 (2)

[匿名]

2010-01-23 9:58 pm

✔ 最佳答案

Reacting the solid with sodium hydroxide solution. Fe3+ gives reddish brown precipitate.

Fe3+ (aq) + OH- (aq) -> Fe(OH)3 (s) <- reddish brown!!

Hope my explanation help.

參考: myself.

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ShingMingTony

2010-01-23 6:15 pm

Test the reddish brown solid with sodium hydroxide solution. If reddish brown percipitaten is form, it contain iron(III) ion

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