Consider a $0.050\;M$ solution of the weak base pyridine ($C_5H_5N$ , $K_b$ $=$ $1.7 \cdot 10^{-4}$)
$C_5H_5N$ $+$ $H_2O$ 
$HC_5H_5N^+$ $+$ $OH^-$
What are the initial molar concentrations of each species (except water)?
a) $0,050\;M$, $0\;M$, $0\;M$ b) $0\;M$, $0,050\;M$, $0\;M$ c) $0,050\;M$, $0,050\;M$, $0,050\;M$ d) $0,050\;M$, $0,050\;M$, $0\;M$
Correct answer: a) $0,050\;M$, $0\;M$, $0\;M$