quiz 8 sec 3 l2 ch 2

The dry test of calcium cation in a calcium chloride solution we must …. at first

• Add a few drops of sulphuric acid

• Neutralize it by NH₄OH

• Heat gently to expel gases

• Evaporate the solution till dryness

Nitrates which are used as fertilizers cause rivers pollutions, because they …

• are salts

• are highly soluble in water

• contain nitrogen

• carry negative charge

Iron (II) sulphide can be obtained from red iron oxide by using a mixture of CO and H₂ gases ... All the following statements are correct, except.…

• both water gas and iron are used as oxidizing agents

• iron (III) oxide can be converted into iron directly

• metals can combine with nonmetals

• iron (II) sulphide is insoluble in water

On adding drops of NaOH solution to the products of the reaction of magnetic iron oxide with hot concentrated sulphuric acid, this results in the formation of …...

• a greenish white ppt. only

• two precipitates, one of them dissolves in HCl

• a reddish-brown ppt. only

• two precipitates, both of them dissolve in HCl

All the following cations can form a precipitate except ……

• Cu2+

• Al³⁺

• Na+

• Ca²⁺

What are the two solutions which when mixed together, the form a precipitate?

• HSO₄ and CuCl₂

• CuCl₂ and Na₂CO₃

• KCl and H₂SO₄

• NaCl and HNO₃

…………… does not dissolve in excess sodium hydroxide solution.

• Zinc hydroxide

• Aluminum hydroxide

• Iron (III) hydroxide

• Tin hydroxide

Why is the detection of cations more complicated than that of anions?

• Because there is a great number of basic radicals

• Because, in some cases, there is more than one oxidation state for the same cation

• Because the basic radicals interfere with each other

• All of the answers are correct

dil. HCl can be considered as ……………

• anion reagent for 1^st analytical group

• Cation reagent for 2^nd analytical group

• Cation reagent for carbonate anion

• anion and cation reagent

The main precipitating agent that used to precipitate calcium salts is …..

• Sodium hydroxide

• Ammonium hydroxide

• Ammonium carbonate

• Iron II sulphate