We are given the base dissociation constant, Kb, for Pyridine (C5H5N) which is 1.4x10^-9. The acid dissociation constant, Ka for the Pyridium ion or the conjugate acid of Pyridine is to be determined. We know from our chemistry classes that:
Kw = Kb * Ka
where Kw is always equal to 1x10^-14
so, to solve for Ka of Pyridium ion, substitute Kb to the equation together with Kw and solve for Ka:
1x10^-14 = 1.4x10^-9 * Ka
solve for Ka
Ka = 7.14x10^-6
Therefore, the acid dissociation constant of Pyridinium ion is 7.14x10^-6.
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Ice has a lower density than the density of water.
A barometer is a tool, not a variable. A barometer measures barometric or air pressure, which is a variable that meteorologists use to predict the weather.
White phosphorus burns spontaneously in chlorine to produce a mixture of two chlorides, phosphorus (ii) chloride and phosphorus(v) chloride and heat is evolved. Phosphorus (iii) chloride is a colorless fuming liquid:
P4 + 6Cl2 = 4PCl3
Phosphorus (v) chloride is an off-white solid
P4 +10Cl2 = 4PCl5