Which of the following are not correctly balanced reactions? Check all that apply.
A. C + Cl2 → CC14
OB. 2K + Br2 + 2KBr
O C. Mg + FeO →2Fe + Mgo
D. C + 02 → CO2

B. 2K + Br2 + 2KBr

D. C + 02 → CO2

Explanation:

In balancing a chemical reaction, the number of atoms on both sides of the expression must be the same in order to obey the law of conservation of mass.

According to the law of conservation of mass, in a chemical reaction, matter is neither created nor destroyed.

 So, let us investigate:

                                                 Number of atoms

                            Reactants                                        Products

K                                  2                                                      2

Br                                 2                                                      2

C + 0₂ → CO₂

C                                1                                                        1

O₂                              2                                                      2

We see that for both equations, the number of atoms on both sides of the expression is the same.