Question 56 of 87

Which of the following is a redox reaction :

1. NaCl + KNO3 NaNO3 + KCl

2. CaC2O4 + 2HCl CaCl2 + H2C2O4

3. Mg(OH)2 + 2NH4Cl  MgCl2

4. Zn + 2AgCN  2Ag + [Zn(CN)2]