Methylamine, CH3NH2, and methylammonium chloride, CH3NH3Cl write the identity of
ID: 500568 • Letter: M
Question
Methylamine, CH3NH2, and methylammonium chloride, CH3NH3Cl
write the identity of the two species in each set (strong acid/strong base/weak acid/weak base/salt/other) and explain reason. Identify if anything in common betweenthe two species .How are the two species in each set are related to each other? If there is a weak acid or a weak base present writethe equation for the dissociation of the weak acid or the weak base. Then label the species in theequation as a weak acid and its conjugate base or a weak base and its conjugate acid. Also determine the Ka for the acid species (if you are dealing with a weak base how could you possibly find a Ka for the acid species in the equation?)Is this mixture a buffer and why?
Explanation / Answer
CH3NH2 is a weak base
CH3NH3Cl is salt
because CH3NH2 + HCl ----------------->CH3NH3Cl
base acid salt
CH3NH2 is a base and CH3NH3Cl is conjugate acid. these are base and acid.
CH3NH2 + H2O --------------------->CH3NH3+ + OH-
base conjugarte acid
Kb of this base = 5.0 x 10^-4
Ka of CH3NH3Cl = Kw / Ka
= 1.0 x 10^-14 / 5.0 x 10^-4
= 2.0 x 10^-11
the mixture of CH3NH2 + CH3NH3Cl is called buffer