Câu 1:
$NaOH\to Na^+ + OH^-$
$Na_2CO_3\to 2Na^+ + CO_3^{2-}$
$H_2S\rightleftharpoons 2H^+ +S^{2-}$
$Fe_2(SO_4)_3\to 2Fe^{3+}+3SO_4^{2-}$
Câu 2:
a,
$H_2SO_4+2NaOH\to Na_2SO_4+2H_2O$
$H^++OH^-\to H_2O$
b,
$Ca(NO_3)_2+Na_2CO_3\to CaCO_3+2NaNO_3$
$Ca^{2+}+CO_3^{2-}\to CaCO_3$
c,
$NH_4Cl+NaOH\to NaCl+NH_3+H_2O$
$NH_4^++OH^-\to NH_3+H_2O$
Câu 3:
Bảo toàn điện tích:
$0,01+0,02=x+2.0,005$
$\Leftrightarrow x=0,02$
$\to m_{\text{rắn}}=0,01.39+0,02.62+0,02.23+0,005.96=2.57g$
Câu 4:
a,
$n_{NaOH}=0,03.0,2=0,006 mol$
$n_{H_2SO_4}=0,02.0,1=0,002 mol$
$\Rightarrow n_{OH^-\text{dư}}=0,006-0,002.2=0,002 mol$
$[H^+]=\dfrac{0,002}{0,03+0,02}=0,04M$
$\to pH=-\lg0,04=1,4$