Introduction to Ammonia and Preparation of Ammonia - Laboratory Method _ From Ammonium salt Flashcards
Ammonia was initially called as
Alkaline air
In 1774 Joseph Priestley prepared ammonia by
Heating slaked lime with sal ammoniac
Joseph priestley called it has alkaline air why
Since it is basic
in 1785 - Who studied chemical composition of the gas
Claude Berthelot
In 1800 who further established its basic composition and proved ammonia to be a compound from the elements of nitrogen and hydrogen
Davy
Ammonia occurs in
Free and chemically combined state
When is Ammonia produce in absence of air
When nitrogenous matter decays in the absence of air
_________ bacteria on organic matter in soil and _________ on nitrogenous organic matter , bring about the decomposition
Putrefying bacteria and Ammonifying bacteria
In the combined state __________ and ____________ are two important source of ammonia
Ammonium salts and Ammoniacal Liquor
Preparation of Ammonia - Laboratory Method - from ammonium salts
Heating of the mixture ammonium salt with alkali - [ Ca[oh]2] slaked lime
salts other than ____________ will not react with alkalis on heating to liberate ammonia
Ammonium salt
Ammonium salts are
White solids , soluble in water , liberate pungent smelling ammonia gas on heating with alkali
Laboratory method - From ammonium salts
Reactants
Ammonium chloride [ NH4CL] and calcium hydroxide [ slaked lime ]
in round bottom flask
Laboratory method - From ammonium salts
Products
Calcium chloride [CACL2] , Water [ H2O] , ammonia [ NH3]
Laboratory method - From ammonium salts
Procedure
The reactants are grounded together and heated slowly in round bottom flask
With its neck slopping Downwards
Laboratory method - From ammonium salts
Observation
The ammonia gas obtained in Flask X passes through delivery tube into drying tower and collected in an inverted gas jar
Laboratory method - From ammonium salts
Drying agents
Quicklime [ CaO] in the drying tower
Laboratory method - From ammonium salts
Precautions
The reactants should be finely powdered form to initiate maximum surface area and slaked lime used should be in higher ratio
The round bottom flask is kept in
Inclined position
NH4NO3 is not used as an Reactant Why ?
Since it is explosive and decomposes
Laboratory method - From ammonium salts
Collection
Ammonia gas is collected by downward displacement of air
Ammonia gas is
Lighter than air
Ammonia gas is highly soluble in water ?
True
Laboratory method - From ammonium salts
Identification
A glass rod dipped in conc. HCl acid is brought near the mouth of glass jar [Y] , If the jar is full dense white fumes of ammonium chloride are formed
Higher ratio of weight of the alkali used
May counteract the loss by Sublimation of ammonium chloride on heating in the solid state
Calcium hydroxide is used Why?
Its cheap
Unlike other Caustic alkali is not deliquescent
Ammonium Nitrate is not used why ?
In the Laboratory since it is explosive and may decompose itself forming nitrate oxide and water vapour
All ammonium salt in general heated with alkali liberate - Ammonia
Round bottom flask is kept in inclined position why?
The reactants being solid are grounded thoroughly to provide maximum surface area for reaction
Heated in Round bottom flask kept in inclined position so that Water vapour formed may not trickle back and crack the hot flask
Drying agent used for drying ammonia
Quick lime [CaO]
Why Quick lime is used ?
Quick Lime being basic in nature does not react with basic ammonium gas
The drying agent which are not used
Conc. H2SO4 , P2O5
fused CaCl2
Since they react chemically with ammonia
How ammonia gas is collected
Ammonia gas is collected by downward displacement of air
since its lighter than air
V.D ammonia = 8.5
V.D air = 14.4
Ammonia gas is not collected over water
Since it is highly soluble in water
