challawar_mayur

 Profile Answers by challawar_mayur 

• May 13th, 2008

 

Generally refrigerants are designated by a code
For a compound in the form Cm Hn Clp Fq
the code is given by
R-(m-1)(n+1)(q)

where 'm' represents no. of carbon atoms
'n' represents no. of hydrogen atoms
'p' represents no. of chlorine  atoms
'q' represents no. of fluorine atoms

The above designation is possible only when n+p+q=2m+2

In case of R-21, we can say it contains 'one' hydrogen atom

'one' fluorine atom,
'one' carbon atom,

Hence to balance the compound it should have two chlorine atoms hence the formula of R21 is C H Cl2 F,therefore R21 is dichloro monofluoro methane

vrsaikumar

 Profile Answers by vrsaikumar Questions by vrsaikumar

• Nov 3rd, 2008

 

Dichlorofluoromethane or Freon 21 or R 21 is a halomethane or hydrochlorofluorocarbon. It is a colorless and odorless gas.
Its critical point is at 178.5 °C (451.7 K) and 517 MPa (51.7 bar). At temperatures from 5 K to 105 K it has one phase in the space group Pbca. 
  Dichlorofluoromethane was used as a propellant and refrigerant, but due to its ozone depletion it has been set to be phased out. It has ozone depletion potential 0.04.

aakashpanchal

 Profile Answers by aakashpanchal 

• May 7th, 2010

 

R21 is C H Cl2 F, therefore R21 is dichloro monofluoro methane.