Do I have to figure grams HCl to figure out?

Question

How many milliliters of 0.1473 M HCl are required to completely neutralize 25.00 mL of 0.1420 M Ba(OH)2?

Answer 1

No, you don't have to calculate the grams of HCl. This problem's all about moles.

First figure out the total moles of Ba(OH)2 to neutralize.

That's (0.1420 mol/L)(25 mL)(1 L/1000 mL) = .00355 mol

You'll need 2 moles of HCl to neutralize each mole of Ba(OH)2 since there are two (OH-) ions in a Ba(OH)2 molecule and only one H+ ion in a HCl molecule... .0071 moles HCl

Then divide the total moles of HCl needed by its concentration to get the liters of HCl solution and convert the answer to mL.
(.0071 mol)/(.1473 mol/L) = .0482 liters = 48.2 mL.

To make sure you understand the solution method, take the time to solve the problem backwards, that is, find how many mL of the barium hydroxide solution are required to neutralize 48.2 mL of the acid. Then the answer will really be yours.

Answer 2

The general rule is gr-eq acid=gr-eq base
and therefore

a(acid)* M(acid)* V(acid)= a(base)* M(base) *V(base)

where a(acid) and a(base) is the valency of the acid and the base respectively (the number of H+ that a molecule of the acid or number of OH- that a molecule of base give)

As long as you are using the same units for volume (ml) for both acid and base you don't need to convert ml to liters and then back to ml. You can directly use ml because the correction factor is simplified in the above equation

So you'll have

1* 0.1473* Vacid= 2* 0.142* 25 =.
Vacid=48.20 ml

***Note: The volume of the base solution is given with accuracy of two decimals. Thus you need to provide the volume of the acid with the same number of decimals, even if the second is 0.

If you haven't learned about gr-eqs yet just use the reaction and its stoichiometry

Ba(OH)2 + 2HCl -> BaCl2 + 2H2O

1 mole Ba(OH)2 reacts with 2 mole HCl
Cbase*Vbase mole Ba(OH)2 react with x mole HCl

therefore x= 2*Cbase*Vbase

but also x= mole acid= Cacid*Vacid

thus Cacid*Vacid = 2* Cbase*Vbase and from here on it is like the solution above.

Answer 3

2 mol of HCL are needed for 1 mol of Ba(OH)2

So,

vol. of HCl needed = (2x25x0.142)/(0.1473) = 48.2 ml

Answer 4

As I recall:

m1 X V1 = m2 X V2


I believe Ag is right.

Answer 5

nope use moles and it will work out. balance the equation and it should be obvious how to attack it. if not go in to teacher for help