Which of the following equations violates the law of conservation of mass?. . 2Al + 6HCl----> 2AlCl3 + 3H2. . Na2C2O4 + Pb(NO3)2----> PbC2O4 + 2NaNO3. . 3Mg + 2Cr(NO3)3 -----> 3Mg(NO3)3 + 2Cr. . AgNO3 + LiCl ----> AgCl + LiNO3