In the reaction CaO(s) + SO2(g) ---> CaSO3(s)
(Hint: try drawing the Lewis structures of SO2 and SO32-)
a. ) Ca2+ acts as a Lewis base, and SO32- acts as a Lewis acid.
b. ) SO32- acts as a Lewis base, and SO2 acts as a Lewis acid.
c. ) O2- acts as a Lewis base, and SO2 acts as a Lewis acid.
d. ) SO2 acts as a Lewis base, and O2- acts as a Lewis acid.
e. ) SO2 acts as a Lewis base, and Ca2+ acts as a Lewis acid.
would it be c)?
I believe c is right. Can this question have more than one answer? What's wrong with answer b?
An electron acceptor is a Lewis acid.
An electron donor is a Lewis base.
dumb
To determine whether Ca2+ acts as a Lewis base and SO32- acts as a Lewis acid or vice versa in the given reaction, we can draw the Lewis structures of SO2 and SO32- to analyze their electron pairs.
First, let's draw the Lewis structure of SO2:
Sulfur has 6 valence electrons, and each oxygen atom has 6 valence electrons.
Step 1: Place the atoms in the structure.
O
|
S=O
|
O
Step 2: Distribute the valence electrons among the atoms.
O
|
S=O
|
O
: :
: :
: :
Step 3: Count the total number of valence electrons and adjust if necessary.
Sulfur has 6 valence electrons, and each oxygen atom has 6 valence electrons. So, the total number of valence electrons is 6 + 2(6) = 18. Since there is a negative charge on SO32-, we add an extra electron, making it a total of 19 valence electrons.
Step 4: Place any remaining valence electrons on the central atom.
Since SO2 has 18 electrons and SO32- has 19 electrons, there are no remaining valence electrons to be placed on the sulfur atom.
Now, let's draw the Lewis structure of SO32-:
Sulfur has 6 valence electrons, and each oxygen atom has 6 valence electrons. The negative charge on the ion implies the addition of one additional electron.
Step 1: Place the atoms in the structure.
O
|
:O=S=O:
Step 2: Distribute the valence electrons among the atoms.
O
|
:O=S=O:
: :
: :
: :
Step 3: Count the total number of valence electrons and adjust if necessary.
Sulfur has 6 valence electrons, and each oxygen atom has 6 valence electrons. So, the total number of valence electrons is 6 + 3(6) + 1 = 25. Since there is a negative charge on SO32-, we add an extra electron, making it a total of 26 valence electrons.
Step 4: Place any remaining valence electrons on the central atom.
Since SO32- has 26 electrons, there are no remaining valence electrons to be placed on the sulfur atom.
Analyzing the Lewis structures, we can see that SO32- has a lone pair of electrons on the sulfur atom, which can act as a Lewis base by donating the electron pair. On the other hand, SO2 does not have any lone pairs on the central atom, making it unable to donate an electron pair. Therefore, the correct answer is option b.) SO32- acts as a Lewis base, and SO2 acts as a Lewis acid.
Keep in mind that Lewis bases are electron pair donors, and Lewis acids are electron pair acceptors.