Question

20 pts if you answer this correctly!!
Which formula represents a double displacement reaction? Ca(OH)2(s) mc009-1.jpg CaO(s) + H2O(g) C2H5OH(I) + O2(g) mc009-2.jpg CO2(g) + H2O(g) Zn(s) + 2HCl(aq) mc009-3.jpg ZnCl2(aq) + H2(g) Pb(NO3)2(aq) + 2HCl(aq) mc009-4.jpg 2HNO3(aq) + PbCl2(s)

Answer 1

I think its the last one i.e.
                                 Pb(NO3)2 + HCl  =   HNO3 + PbCl2