Chemistry
When ammonium hydroxide is added to solution B, a pale blue precipitate is formed. This pale blue precipitate dissolves in excess ammonium hydroxide giving an inky blue solution. What is the cation (positive ion) present in solution B? What is the probable colour of solution B.
Answer
Solution B is Copper Sulphate and cation present is (Cu2+). The colour of solution B is Blue.
Ammonium hydroxide gives a blue precipitate when it combines with a solution of copper salt, due to the formation of Cu(OH)2
CuSO4 + 2NH4OH ⟶ (NH4)2SO4 + Cu(OH)2 ↓
The pale blue precipitate of copper hydroxide dissolves in excess of ammonium hydroxide forming tetraamine copper [II] sulphate, an azure blue soluble complex salt.
Cu(OH)2 + (NH4)2SO4 + 2NH4OH ⟶ [Cu(NH3)4]SO4 + 4H2O
Related Questions
Give balanced equations for the following conversions :
(a) Ammonia to nitrogen using an acidic gas.
(b) Ammonia to brown gas.
(c) Ammonia to nitrogen trichloride
(d) Ammonia solution to an amphoteric hydroxide
(e) A nitride of a trivalent metal to ammonia
(f) Lead oxide to lead
Name:
(a) the gas which is prepared by Haber's process.
(b) two gases which give dense white fumes with ammonia.
(c) one salt of ammonia in each case which is used in:
(i) dry cell
(ii) explosives
(iii) medicine
(d) an acidic gas which reacts with a basic gas liberating a neutral gas
(e) a metallic chloride soluble in ammonium hydroxide
(f) the gas obtained when ammonia burns in an atmosphere of oxygen without any catalyst
(g) a nitride of a divalent metal which reacts with warm water liberating ammonia
(h) an amphoteric oxide reduced by the basic gas
(i) a white salt produced by an acidic gas and a basic gas
When an ammonium salt is warmed with sodium hydroxide solution, a gas is evolved. State three ways in which you could identify this gas.
A gas 'A' reacts with another gas 'B' in the presence of a catalyst to give a colourless gas 'C'. The gas 'C' when comes in contact with air produces a brown gas 'D'. The solution of 'A' in water turns red litmus blue. Explain the observations.