# Question #ed2aa

##### 1 Answer

#### Explanation:

The idea here is that in order for the titration to reach its **equivalence point**, the strong base must be **completely neutralized** by the strong acid.

In practice, we can determine when the neutralization reaction is complete by looking for the **endpoint** of the titration, which occurs when the indicator *changes color*.

If we did a good job at picking the indicator and at performing the titration, then we can use the endpoint and the equivalence point *interchangeably*.

#overbrace(2"NaOH"_ ((aq)))^(color(blue)("2 moles consumed")) + overbrace("H"_ 2"SO"_ (4(aq)))^(color(blue)("1 mole consumed")) -> "Na"_ 2"SO"_ (4(aq)) + "H"_ 2"O"_ ((l))#

Notice that each mole of sulfuric acid can neutralize **moles** of sodium hydroxide.

You know that in order to get to the endpoint, the reaction consumed

#40 color(red)(cancel(color(black)("mL"))) * ("0.05 moles H"_2"SO"_4)/(10^3color(red)(cancel(color(black)("mL")))) = "0.0020 moles H"_2"SO"_4#

This means that the sodium hydroxide solution contained

#0.0020 color(red)(cancel(color(black)("moles H"_2"SO"_4))) * "2 moles NaOH"/(1color(red)(cancel(color(black)("mole H"_2"SO"_4)))) = "0.0040 moles NaOH"#

Since you know that the volume of the sodium hydroxide solution was equal to **in liters**!

#["NaOH"] = "0.0040 moles"/(50 * 10^(-3) quad "L") = color(darkgreen)(ul(color(black)("0.08 M")))#

The answer is rounded to one **significant figure**.