The case of the availability of liquid ammonia and it’s water like properties have made it a very useful solvent and reaction medium for carrying out various types of organic and inorganic synthesis. 
Some important characteristics of ammonia as a solvent are as follows:

1) Like water, ammonia molecules are associated through 
hydrogen bonding in liquid ammonia as it has a strongly 
electronegative nitrogen atom which is responsible for 
hydrogen bonding in it.

2) A protonic solvent Liquid ammonia is a protonic solvent and 
ionizing solvent.

3) The dielectric constant of liquid ammonia makes possible to 
carryout many reactions and thus to some extent compensate 
the dielectric effect which favours lesser reaction. 
4) In general, solubilities of covalent organic compounds in liquid 
ammonia are considerably higher than in water probably 
owing to the greater dispersion energy interaction.

5) The freezing and boiling points of liquid ammonia are lower 
than those of water.  Therefore, more precautions are to be 
taken while handling liquid ammonia.

6) Liquid ammonia possesses usually high thermal coefficient of 
expansion i.e. it’s density decreases with rise of temperature. 
Auto- ionization of liquid ammonia:- 
The extent of auto-ionization of liquid ammonia is less than 
that of water.

2NH3             NH4+  +  NH2- 
 
2H2O                H3O+  + OH- 
 
It is indicated from it’s low specific conductance and also 
from it’s ionic product. i.e. 
KH2O =[H3O+] [OH-]=1×10-14 at 18°c 
 
 KNH3=[NH4+] [NH2-]=1.9×10-33at 55°c 
Ammonium ion liquid ammonia is analogous to 
H3O
+
solution and amide ion NH2- to OH- ion. Hence any 
substance which gives NH4+  ions in liquid ammonia acts as 
acid and is known as ammonia acid.e.g., NH4CL. Any 
substance which gives NH2- ion acts as base and is known as 
ammonia base.e.g.Sodamide NaNH2. On the basis of Bronsted 
Lowry Concept. NH4
+ ions would behaves as acids and amide 
as bases in liquid ammonia. 
Solubility Of Substances in liq.NH3

➢ Inorganic Compounds:- 
Since dielectric constant of NH3 is much less than that of 
H2O,in liq.NH3 is poorer solvent for Ionic substances. 
Molecules having many electrons such as iodine 
compounds and non- polar substances such as 
hydrocarbons are, however,soluble in liq.NH3. Nitrates, 
thiocyanates, perchlorates and most cyanide are soluble 
in liquid ammonia. Oxides , hydroxides , sulphates 
carbonates, phosphates,sulphites and most sulphides are 
insoluble. Most of the ammonium salts such as NH4NO3,NH4SCN ,CH3COONH4, are 
soluble in liq. Ammonia. All the metal amides , except 
those of alkali metals are insoluble.

➢ Organic Compounds:- 
Alcohols , halogen compounds (e.g. Chloroform etc), 
ketones, esters , simple ethers and phenol and it’s 
derivatives are soluble. The aromatic hydrocarbons are sparingly soluble  ➢ Non-metals:- 
The non- metals (e.g.P,S and I) dissolve in liq.NH3 reacting 
With it. 
5/4 S8 + 16NH3                             N4S4+6(NH4)2S 
 
❖ Advantages of liquid NH3 as a solvent:

i. On the other hand liq. NH3 is better solvent than water for iodine 
compounds and many non -polar 
compounds,i.e. hydrocarbons.

ii. Liquid NH3 dissolves alkali metals without apparent chemical reaction 
but water does not . 
                  M+H2                MOH +H2     
III.  Liquid ammonia has little solvoly tendency than H2O towards the dissolved 
     Solutes (Ammonolysis reactions are less than solvolysisReactions).

❖ Disadvantages of using liquid NH3 as a solvent:

i. The use of liquid ammonia as a solvent and a reaction medium required elaborate equipment and special techniques are to be used .

ii. The boiling point of liquid ammonia is 239.5K(-33.5°) and hence while working with this solvent,a lower temperature is to be maintained, if high pressure are to beavoided. 
iii. Due to hygroscopic nature of liquid ammonia reactions are done in sealed tubes so as not to allow ammonia to come in contact with moisture. 
 
➢ Types of Chemical reactions occuring 
in liquid ammonia:

▪ Acid- base reactions: 
As substances producing H3O+ ions in water are acids. similarly ammonium salts giving NH4+ ions in liquid ammonia are acids. Similarly Substances producing OH-  ions in water and NH2- ( amide) ions in liquid ammonia are bases in that solvents. According to Bronsted Lowry 
Concept of acids and bases, the ionization reaction taking place in H2O and NH3 are similar. 
Consider the auto- ionization of H2O and liq.NH3 ; H2O+H2O                    H3O+ + OH- NH3 + NH3                            NH4+ +NH2- 
 
Thus
 NH4+ salts will act as Acids; where as NH2- salts 
will act as bases in which liquid ammonia. Acid base results 
in the formation of salt and solvent in which the reaction is 
carried out. 
NH4NO3 + KNH2                              KNO3 +2NH3 
NH4Cl + KNH2                                 KCl + 2NH3 
Ammonium salts can also dissolves metal oxides and 
hydroxides. 
NH4Cl+CaO                CaCl2+2NH3+H2O 
NH4NO3+NAOH                NaNO3+NH3+ H2O 
▪ Redox Reactions: 
Redox reactions are those in which nitrogen or 
hydrogen of ammonia molecule undergo a change in 
it’s oxidation number. Some important redox 
reactions occuring in liq.NH3 are given below.

➢ Catalytic oxidation of NH3 to NO 
4NH3+ 5O2                         4NO+6H2O

➢  Reduction of metal oxide with liquid ammonia 
3CuO+2NH3                        3Cu+3H2O+N2

➢ Addition of metallic Na in liq.NH3 to NH4Br is a 
redox reaction. 
2Na+2NH4Br            2NaBr+2NH3+H2 
 
▪ Precipitation Reactions:  

 Precipitation reactions are similar to those of H2O however the compound which are insoluble in liquid ammonia vary considerably from those which are insoluble in H2O. Most metal chlorides are insoluble in liq.NH3 except,NaCl,NH4Cl and BeCl2 e.g. 
 
KI+NH4Cl                  KCl     +NH4I 
 
2AgCl+KNO3               KCl    +AgNO3 
 
2AgCl+BaNO3                     BaCl2+2AgNO3 
 
▪ Complex Formation Reactions: 
Many complex formation reactions in liq.NH3 have been studied which are similar to reactions occuring in water system. I. Many insoluble metal amides,imides and nitrides dissolve in solution of KNH2 in liquid ammonia to from soluble amido  
Complex,e.g. 
Zn(NO3)2+2KNH2                     Zn(NH2)2+2KNO3 
 
Zn(NH2)2+2KNH2                    K2[Zn(NH2)4] 
Soluble amido complexx

 ▪ Solvolysis/ Ammonolysis Reactions: 
Reactions are similar to hydrolysis reactions in H2O,in 
Ammonolysis Reactions NH3 acts as a reactante.e.g. 
 
Hg2Cl2+2NH3                    Hg°+NH4Cl+Hg(NH2)Cl 
BCl3+6NH3                          B(NH2)4+4NH4Cl 
 
▪ Solvation/Ammonation Reactions: 
Ammonation reaction are those in which one or more molecules of 
liquid ammonia are attached with the solute species containing an 
accepter atom by any of the chemical linkage and give the 
products, known as Ammoniates. In this case NH3 molecule act as 
Lewis base since it has a lone pair, donate electron. 
 
BF3+ NH3                                  BF3.NH3 
SO2+2NH3                             SO2.2NH3 
MgI2+6NH3                          MgI2.6NH3

▪ Amphoteric Reactions: 
Like water amphoteric behavior is also shown in liquid ammonia. 
Many metallic amides are amphoteric like many oxides and 
hydroxides e.g. 
In liquid ammonia, 
ZnCl2+2KNH2                      Zn(NH2)2+2KCl 
Zn(NH2)2+2KNH2                      K2[Zn(NH2)4] 
 
In H2O, 
ZnCl2+2KOH               Zn(OH)2+2KCl 
Zn(OH)2+2KOH              K2[Zn(OH)4]

 Study Of Reactions in liquid Sulphur Dioxide: 
Liquid SO2 is a water like solvent and as such is used extensively for 
carrying out a number of Chemical reactions. 
 
General Characteristics:

i. Non protonic solvent

ii. It is boils at -10°C and freezes at -75.5°C. since the liquid 
range is sufficiently high ,it can work as a good solvent.

iii. It has low dielectric constant. Therefore it is better 
solvent for covalently bonded structures. 
Chemical Reactions in liquid SO2. 
Chemical reactions that can occur in liq.SO2 are as follows:

1. Acid- base reactions: 
Liquid SO2 undergoes auto ionization to about same extent as 
does water

SO2+SO2                       SO+2 + SO3-2 
Acid thionyl base sulphite The compounds which contains SO+2ions would expected to behave as acids, while the compound which contain SO+3ions would be expected to based in liq.SO2 e.g. 
SOCl2 +Cs2SO3                          2CsCl + 2SO2 2. Precipitation Reactions: 
There are many Precipitation reactions which may conveniently 
be carried out in liq.SO2 due to specific solubility relationship. 
The Precipitation of several insoluble substances upon mixing 
the soluble compounds in liq.SO2 are as follows: 
SbCl3 + 3LiI               SbI3    + 3LiCl 
 
2KI + SOCl2                      SOI2 + 2KCl 3.

Redox Reactions: 
Liq.SO2  acts as an inert medium.it does not behaves it self as 
oxidizing and reducing agent.it only serves as a medium to carryout 
redox reactions.e.g. 
6KI + 3 SbCl5                       3I2 + SbCl3+2K3[SbCl6] 
2FeCl3+2KI             2FeCl2+2KCl+I2 4.

Amphoterism Reactions: 
 They occur in liq.SO2 just like in aqueous medium e.g. AlCl3+3OH-                       Al(OH)3     + 3Cl- 
Al(OH)3 + OH-                         [Al(OH-)4] soluble 
complex 5. Solvation Reaction: 
The high solubilities of certain salts in liq. SO2 are believed to be 
due to solvate formation.e.g. 
RbI + 3SO2                          RbI.SO2 
TiBr4 + SO2                         TiBr.SO2 6. Reactions of Organic Compounds: 
Since many organic compounds are soluble in liq.SO2 and itself 
inert to many of them, a range of synthetic organic reactions has 
been carried out in this solvent.e.g. 
 
 
1) Sulphonation: 
 

 
 
2) Friedal- Crafts Reactions: 
Liq.SO2 has also been used as a sovent for Friedal
Crafts reactions because of high solubility of AlCl3 in 
it. 
It is very useful solvent for various types of synthetic reactions and 
in the refining of petroleum. 3) Bromination Reactions: 
It has also been used as a solvent for the addition of 
bromine to understand compounds. 
 
 
 Study Of Reactions in liquid HF: 
HF is one of the most water like of all the aqueous solvents. The 
properties i.e,  ➢ Liquid range from-83 to 19.4°C ➢ Low specific conductance ➢ High dielectric constant makes it an excellent ionizing 
solvent. 
Chemical reactions of HF: 
Liquid HF is a strongly acidic solvent.it has relatively higher 
degree of auto-ionization. 
1.  Acid base reactions: 
HF like H2O,NH3 and SO2 undergoes auto ionization to give HF - 
and H+ ions . The acid-base reactions also carried out in liquid HF  SbF5+ HF              [SbF6]-1 +H+ 
 
2.Redox reactions:  
Redox reactions can also be carried out liq.HF e.g. 
4HNO3+3Ag             3AgNO3+ NO+2H2O 
3. Precipitation Reactions: 
Only few anions i.e., SO4
2- ,ClO4
2
IO4- are soluble in HF. They give 
Precipitation Reactions in liquid HF. 
BF3+ AgF              B[AgF4] 
4. Complex Formation Reactions: 
Complex Formation Reactions are also occurs in liq.HF e.g, 
 
CrF3+3NaF               Na3[CrF6]