If a 25.0 ml sample of sulfuric acid is titrated with 50.0 ml of 0.200 m potassium hydroxide to a phenolphthalein endpoint, what is the molarity of the acid?

a) 0.150 m
b) 0.100 m
c) 0.200 m
d) 0.300 m
e) 0.400 m

Molarity of the sulfuric acid is Choice C): 0.200 M.

Explanation:

The unit for molarity "M" stands for moles per liter. Convert all volume to liters:

How many moles of potassium hydroxide is required to reach the equivalence endpoint?

.

How many moles of sulfuric acid in the original solution?

neutralizes at a two-to-one ratio:

.

The moles of will neutralize only half as much . That is:

.

What's the molarity of the solution?

.