a) 2C2H5COOH+Mg--->(C2H5COO)2Mg+H2
2C2H5COOH+MgO--->(C2H5COO)2Mg+H2O
2C2H5COOH+Mg(OH)2--->(C2H5COO)2Mg+2H2O
b) 6HCOOH+2Cr--->2(HCOO)3Cr+3H2
6HCOOH+Cr2O3--->2(HCOO)3Cr+3H2O
3HCOOH+Cr(OH)3--->(HCOO)3Cr+3H2O
c) 2C6H13COOH+2Li--->2C6H13COOLi+H2
2C6H13COOH+Li2O--->2C6H13COOLi+H2O
C6H13COOH+LiOH--->C6H13COOLi+H2O