Classify each of these reactions.

$\backslash$table$[[$Reaction$,$Type$],[Pb(N{O}_3{)}_2(aq)+2KCl(aq)longrightarrowPbC{l}_2(s)+2KN{O}_3(aq),],[C{H}_4(g)+2O_2(g)longrightarrowC{O}_2(g)+2H_{2}O(l),],[Cu(s)+FeC{l}_2(aq)longrightarrowFe(s)+CuC{l}_2(aq),],[2$KOH$(aq)+H_{2}S{O}_4(aq)longrightarrow{K}_{2}S{O}_4(aq)+2H_{2}O(l),]]$