Alyssa is trying to balance the following equation: Pb (OH) 2 + 2H2SO4 = > PbSO4 + 2H20 What number should be used to replace the question mark (?) shown in the equation above to balance it? O a. 3 O b. 1 Oco O d. 2 Oe. 4

2 Pb (OH) 2 + 2H2SO4 = > 2 PbSO4 + 4 H20

Explanation:

Since there's no "?" shown in the equation, let's balance it and solve it entirely.

Pb (OH) 2 + 2H2SO4 = > PbSO4 + 2H20

1Pb + 10O + 6H + 2S ≠ 1Pb + 6O + 4H + 1S → it needs to be balanced.

To do this, let's start by looking at the elements that are only presnet once on each side:

On the products half, S is only present in PbSO4 → if we look at the reagents half, we can see it needs a "2" → then Pb is multiplied by 2 too → so Pb (OH) 2 on the reagents half will also need a "2" → final count on O and H on the reagents side: 12O and 8H → to balance it, you need 4 water molecules on the products side.