Which of the following reactions would be fastest at room temperature under normal pressure?

1)CH4(g) + 2 O2(g) CO2(g) + 2 H2O(g)

2) 2 CH3COOH(aq) + Ba(OH)2(aq) Ba(CH3COO)2(aq) + 2 H2O(l)

3)KCl(aq) + AgNO3(aq) KNO3(aq) + AgCl(s)

4) 2 Li(s) + 2 H2O(l) 2 LiOH(aq) + H2(g)