Experiment 2.7

№ experiment	Description of the experiment
	Place 2-3 drops of 0.5N chrome (ІІІ) chloride solution, 4-6 drops of concentrated sodium hydroxide solution into each of two test tubes and add: the excess amount of bromine water into the first tube, the excess amount of hydrogen peroxide solution into the other one. What can you observe? What is the role of chrome (ІІІ) in these reactions? Give the equations of the relevant reactions.
Observations
Equation of reaction

Experiment 2.8

№ experiment	Description of the experiment
	Place 2-3 drops of potassium dichromate solution into a test tube and add 2-3 drops of diluted alkali solution. What can you observe? Give the equation of the reaction.
Observations
Equation of reaction

Experiment 2.9

№ experiment	Description of the experiment
	Place 2-3 drops of potassium chromate solution into a test tube and add 2-3 drops of diluted hydrochloric acid. What can you observe? Give the equation of the reaction.
Observations
Equation of reaction

Experiment 2.10

№ experiment	Description of the experiment
	Place 6-7 drops of potassium dichromate solution into each of three test tubes and add 2-3 drops of diluted sulphuric acid into each tube. After that add 3-5 drops of 0.5N potassium iodide solution into the first test tube, the same amount of 0.5N sodium nitrite solution into the second one, and the same amount of 0.5N sodium sulphite solution into the third one. If necessary, heat up the test tubes slightly. What can you observe? Give the equations of the reactions.
Observations
Equation of reaction

Chemical properties to molybdenum and tungsten

Experiment 3.1

№ experiment	Description of the experiment
	Place 2-3 ml of 0.5N ammonium molybdate solution into a test tube, add 3-4 drops of concentrated hydrochloric acid and 1-2 granules of metallic zinc. What occurs? Give the equations of the relevant reactions, taking into account, that the following compounds are formed: (NH4)2[MoOCl5] is green, and (NH4)4[MoOCl4] is brown.
Observations
Equation of reaction

Experiment 3.2

№ experiment	Description of the experiment
	Place 2-3 ml of 0.5N ammonium molybdate solution into a test tube and add by drops diluted nitric acid, avoiding its excess amount, until precipitate forms. Divide the precipitate in two parts in two test tubes and add excess amount of 1M hydrochloric acid solution to one of them, and excess amount of 1M sodium hydroxide solution to the second. What occurs? Give the equations of the relevant reactions and make a conclusion of acid-base properties of the compound.
Observations
Equation of reaction

Experiment 3.3

№ experiment	Description of the experiment
	Place 2-3 ml of 0.5N ammonium tungstenate solution into a test tube and add by drops diluted nitric acid, avoiding its excess amount, until precipitate forms. Divide the precipitate in two parts in two test tubes and add excess amount of 1M hydrochloric acid solution to one of them, and excess amount of 1M sodium hydroxide solution to the second. What occurs? Give the equations of the relevant reactions and make a conclusion of acid-base properties of the compound.
Observations
Equation of reaction

Дата добавления: 2015-10-29