Question

In the equation below, how many molecules of Cl2 are required to react completely with 2 atoms of sodium?

2 Na(s) + Cl2(g) ---> 2 NaCl(s)

Select one:
a. 1
b. 2
c. 3
d. 4​

Answer 1

a. 1

Step-by-step explanation:

2Na + Cl2 ---> 2NaCl

Only one molecule of Cl2 is required to react.
Remember the concept, the little number, or the subscript represents the number of atoms in a molecule. The coefficient or the big number before a molecule represents the number of molecules. There is no coefficient in the reaction before Cl2 therefore only 1 molecule is needed to completely react with 2 atoms of sodium.