Chemistry Help

Question

In a 1985 study of Little Rock Lake in Wisconsin, 400 gallons of 18M sulfuric acid were added to the lake over six years. The initial pH of the lake was 6.1 and the final pH was 4.7. If none of the acid was consumed in chemical reactions, estimate the volume of the lake

Answer 1

Assuming that only the first dissociation of H2SO4 is considered ...

400 gal x 3.79 L/gal = 1516 liters of 18 M H2SO4

1516 L x 18 moles/L = 27,288 moles H+ added

From pH = 4.7, [H+] = 1x10^-4.7 = 2x10^-5 M

2.7x10^4 mole/x L = 2x10^-5 mole/1 L

x = 1.35x10^9 liters

 

1.35x10^9 L x 1 gal/3.79 L = 3.6x10^8 gallons = 360,000,000 gallons