a, PT điện ly: `NaOH\to Na^{+}+OH^{-}`
$\Rightarrow [Na^+]=[OH^-]=C_{M_{NaOH}}=0,01\ (M)$
b, PT điện ly: `K_2CO_3\to 2K^{+}+CO_3^{2-}`
$\Rightarrow \begin{cases}[K^+]=2C_{M_{K_2CO_3}}=2.0,02=0,04\ (M)\\\   [CO_3^{2-}]=C_{M_{K_2CO_3}}=0,02\ (M)\end{cases}$
c, PT điện ly: `Al_2(SO_4)_3\to 2Al^{3+}+3SO_4^{2-}`
$\Rightarrow \begin{cases}[Al^{3+}]=2C_{M_{Al_2(SO_4)_3}}=0,5\ (M)\\\  [SO_4^{2-}]=3C_{M_{Al_2(SO_4)}}=0,75\ (M)\end{cases}$