Question

PLEASE HELP!!!!!!

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

Answer:
`Pb(NO_3)_2(aq)+2HCl(aq)\rightarrow 2HNO_3(aq)+PbCl_2(s)`

Step-by-step explanation: 1.
`Ca(OH)_2(s)\rightarrow CaO(s)+H_2O(g)`

This is an example of decomposition reaction in which one reactant gives two or more than two products on absorption of energy.

2.
`C_2H_5OH(I)+O_2(g)\rightarrow CO_2(g)+H_2O(g)`

This is an example of combustion reaction in which hydrocarbon burns in the presence of oxygen to form carbon dioxide, water and energy.

3.
`Zn(s)+2HCl(aq)\rightarrow ZnCl_2(aq)+H_2(g)`

This is an example of single replacement reaction in which a more reactive element displaces a less reactive element from its salt solution.

4.
`Pb(NO_3)_2(aq)+2HCl(aq)\rightarrow 2HNO_3(aq)+PbCl_2(s)`

This is an example of a double displacement reaction in which exchange of ions take place.