Question

в трех склянках без этикеток находятся растворы солей: в одной-хлорида цинка, в другой-хлорида меди(2), в третьей - хлорида кальция. Докажите,используя реактив,какое вещество находится в каждой из склянок.Напишите уравнения соответствующих реакций. Назовите соли

Answer 1

В качестве реактива нам понадобится в принципе любая щёлочь. Например, NaOH.

 

1) ZnCl2 + 2NaOH = 2NaCl + Zn(OH)2↓

Увидим белый студёнистый осадок Zn(OH)2, который растворяется в избытке щёлочи.

 

2) CuCl2 + 2NaOH = 2NaCl + Cu(OH)2↓

Раствор становится голубым, появляется голубой осадок Cu(OH)2.

 

Собственно, в последней пробирке находится CaCl2.

 

Answer 2

Identification of Substances in the Unlabeled Glass Containers

To determine the substances present in each of the unlabeled glass containers, we can perform specific reactions using appropriate reagents. Based on the provided information, we have three glass containers containing solutions of zinc chloride, copper(II) chloride, and calcium chloride.

1. Zinc Chloride (ZnCl2): To confirm the presence of zinc chloride, we can add sodium hydroxide (NaOH) solution to the first glass container. If zinc chloride is present, a white precipitate of zinc hydroxide (Zn(OH)2) will form according to the following reaction: ``` ZnCl2 + 2NaOH → Zn(OH)2 + 2NaCl ```

2. Copper(II) Chloride (CuCl2): To identify copper(II) chloride, we can add sodium hydroxide (NaOH) solution to the second glass container. If copper(II) chloride is present, a blue precipitate of copper(II) hydroxide (Cu(OH)2) will form according to the following reaction: ``` CuCl2 + 2NaOH → Cu(OH)2 + 2NaCl ```

3. Calcium Chloride (CaCl2): To determine the presence of calcium chloride, we can add sodium carbonate (Na2CO3) solution to the third glass container. If calcium chloride is present, a white precipitate of calcium carbonate (CaCO3) will form according to the following reaction: ``` CaCl2 + Na2CO3 → CaCO3 + 2NaCl ```

By performing these specific reactions, we can confirm the presence of zinc chloride, copper(II) chloride, and calcium chloride in the respective glass containers.

Please note that the reactions mentioned above are based on general chemical principles. The actual reactions may vary depending on the specific conditions and concentrations of the solutions.