Three flasks contain solutions of salts: one contains zinc chloride, the other contains

| September 24, 2021 | education

Three flasks contain solutions of salts: one contains zinc chloride, the other contains copper chloride (2), and the third contains calcium chloride. Prove, using the reagent, which thing is in each of the flasks. Write the equations of the corresponding reactions. Write the salts

Add alkali NaOH to all tubes.

In a test tube with zinc chloride, a white precipitate will form – zinc hydroxide.

ZnCl2 + 2 NaOH = Zn (OH) 2 + 2 NaCl.

In a test tube with copper chloride, a blue precipitate will form – copper (II) hydroxide.

CuCl 2 + 2 NaOH = Cu (OH) 2 + 2 NaCl.

In a test tube with calcium chloride, a white, slightly soluble precipitate of Ca (OH) 2 will precipitate.

CaCl2 + 2 NaOH = Ca (OH) 2 + 2Na Cl.

To determine in which test tube zinc hydroxide and in which calcium hydroxide, add phenolphthalein. In a test tube with calcium hydroxide, it will acquire a crimson color, since calcium hydroxide is an alkali that can change the color of indicators.



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