Answer : Option 3) Electrolysis.
Explanation : In the process of electrolysis, decomposition of the chemical is done by passing the electric current from the liquid or the solution containing ions in it. This is the process where compound is broken into ions namely, cations and anions.
Rest all options does not involves chemical decomposition of the compound.
Chromatography is a technique where rates of solute and solvent are compared in a medium where the solute components move at different rates and the separation is obtained.
Distillation simply purifies the liquid or solution by heating or cooling process.
Filtration just involves removal of impurities by using a more porous material device to get purified compound.
Filtration
hope this helped
Answer:
Partial pressure of dinitrogen tetroxide after equilibrium is reached the second time is 0.82 atm.
Explanation:

Initially
3.0 atm 0
At equilibrium
(3.0-2p) p
Equilibrium partial pressure of 
p = 0.45 atm
The value of equilibrium constant wil be given by :


After addition of 1.5 atm of nitrogen dioxide gas equilibrium reestablishes it self :

After adding 1.5 atm of
:
(2.1+1.5) atm 0.45 atm
At second equilibrium:'
(3.6-2P) (0.45+P)
The expression of equilibrium can be written as:


Solving for P:
P = 0.37 atm
Partial pressure of dinitrogen tetroxide after equilibrium is reached the second time:
= (0.45+P) atm = (0.45 + 0.37 )atm = 0.82 atm
Partial pressure of dinitrogen tetroxide after equilibrium is reached the second time is 0.82 atm.