Question

Which of the following demonstrates a double-replacement reaction?
A: Na3PO4 + MnCl2 > Mn3(PO4)2 + NaCl
B: CaCO3 > CaO + CO2
C: 2Mg + O2 > 2MgO
D: 2AgNO3 + Cu > 2Ag + Cu(NO3)2

Answer 1

A: Na3PO4 + MnCl2 > Mn3(PO4)2 + NaCl

Answer 2

Answer: The correct answer is Option A.

Explanation:

For the given options:

Option A:  $Na_3PO_4+MnCl_2\rightarrow Mn_3(PO_4)_2+NaCl$

This reaction is considered as a double displacement reaction because here exchange of ions takes place.

Option B:  $CaCO_3\rightarrow CaO+CO_2$

This reaction is considered as a decomposition reaction because here one substance is breaking into two smaller substances.

Option C:  $2Mg+O_2\rightarrow 2MgO$

This reaction is considered as a synthesis reaction because here two smaller substances are combining in their elemental state to form a single large substance.

Option D:  $2AgNO_3+Cu\rightarrow 2Ag+Cu(NO_3)_2$

This reaction is considered as a single displacement reaction because here more reactive element displaces a less reactive element from its chemical reaction.

Hence, the correct answer is Option A.