Question

Question #9c03b

Answer 1

The molarity of the sulfuric acid solution will be `"17.1 M"`.

You are dealing with a neutralization reaction - in this case, a strong acid and a strong base react to produce salt and water. The balanced chemical equation looks like this

`2NaOH + H_2SO_4 -> Na_2SO_4 + 2H_2O`

SIDE NOTE - the reaction takes place in aqueous solution; taht being said, I won't go into the net ionic equation

Now look at the mole ratio you have between `NaOH` and `H_2SO_4` - 2 moles of the former react with 1 mole of the latter. A neutralization reaction implies that both the acid and the base are consumed, i.e. the two cancel each other out.

This means that the number of `H_2SO_4` moles depends on the number of moles of `NaOH`, which you can determine by using its molar mass, and on the mole ratio between the two compounds

`"112.0 g" * ("1 mole")/("40.0 g") = "2.80 moles NaOH"`

Apply the aforementioned mole ratio to see exactly how many moles of `H_2SO_4` were neutralized by this much `NaOH`

`"2.80 moles NaOH" * ("1 mole"H_2SO_4)/("2 moles NaOH") = "1.40 moles"` `H_2SO_4`

The last thing to do is use the formula for molarity

`C = n/V = ("1.40 moles")/(82.0*10^(-3)"L") = "17.1 M"`

Don't forget to transform mL into L, since molarity uses liters, not mililiters!

Answer 2

First convert the weight of `NaOH` to moles.

Relative atomic masses are `Na=23,O=16,H=1`
For a total molecular mass `NaOH=40`

So `112.0g` converts to `112.0/40=2.8mol`

Since sulfuric acid `H_2SO_4` has two `H^+`-ions it neutralises in a ratio of 2:1, so there must have been `2.8//2=1.4mol` of sulfuric acid.

The molarity of the solution= `(mol)/L.`

Molarity = `(1.4"mol")/(82.0mL)=(1.4mol)/(0.082L)~~17.1mol//L`

Which is a very strong solution -- you may (almost) call this concentrated sulfuric acid. Don't spill it on your skin!

Extra :
Let's call this a thought experient. You would NOT want to do this in practice, not even in a fume cupboard, as the result will get explosive due to the extreme heat developed in this reaction!