# hiw many oh- are in ba(oh)2 And how many h+ in h2so4

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2 OH- in Ba(OH)2 and 2 H+ in H2SO4

Why do we multiply by 2 if we already have 2
Original post by Roxibox123

Why do we multiply by 2 if we already have 2

What have you worked out so far?
How many mols of H do we have in 0.05 sulfuric acid?
How many moles of OH do we have in each of the given solutions?
Original post by booklover1313
What have you worked out so far?
How many mols of H do we have in 0.05 sulfuric acid?
How many moles of OH do we have in each of the given solutions?

0.05
0.2
0.2
0.05
Think of it as the equation :
H2SO4 ---> 2H+ + SO42-

The 0.05 moles is of sulfuric acid not the moles of H+ in the solution so you need to multiply it by 2 to get the moles of H+, which is 0.1 moles.

In the same way,
Ba(OH)2 ---> Ba2+ + 2OH-
so eg. for D there are 0.05 x1= 0.05 moles of Ba(OH)2 but as there is a 1:2 ratio of Ba(OH)2 and OH-, you need to multiply the moles by 2 to get moles of OH-. So 0.05 x 2 = 0.1 moles of OH- in D that will react with the 0.1 moles of sulfuric acid to neutralise it.
Original post by AA321123
Think of it as the equation :
H2SO4 ---> 2H+ + SO42-

The 0.05 moles is of sulfuric acid not the moles of H+ in the solution so you need to multiply it by 2 to get the moles of H+, which is 0.1 moles.

In the same way,
Ba(OH)2 ---> Ba2+ + 2OH-
so eg. for D there are 0.05 x1= 0.05 moles of Ba(OH)2 but as there is a 1:2 ratio of Ba(OH)2 and OH-, you need to multiply the moles by 2 to get moles of OH-. So 0.05 x 2 = 0.1 moles of OH- in D that will react with the 0.1 moles of sulfuric acid to neutralise it.

Where did the 2H+ and oh- come from and what type of equation is this
Original post by Roxibox123
Where did the 2H+ and oh- come from and what type of equation is this

That's how they dissociate in solution. H2SO4 has two hydrogens so dissociate into 2H+. Ba(OH)2 has 2 OH groups so dissociate into 2 OH-

Ionic equations.
Original post by AA321123
That's how they dissociate in solution. H2SO4 has two hydrogens so dissociate into 2H+. Ba(OH)2 has 2 OH groups so dissociate into 2 OH-

Ionic equations.

Yeah so why do we times by 2 if they already have 2
Original post by Roxibox123
Yeah so why do we times by 2 if they already have 2

Because if you don't multiply by 2 it's the H2SO4 concentration not the H+ concentration. Read my first response and think of it as the equations and ratios of acid to H+ and that'll make it easier
Original post by Roxibox123
Yeah so why do we times by 2 if they already have 2

with the sulfuric acid, H2SO4, that dissociates to 2H+ and SO42-
So for each molecule of sulfuric acid, you have 2 H+
So 1 mol of sulfuric acid will produce 2 mol H+
We only have 0.05mol of sulfuric acid in the question, and so we therefore get 0.05 x 2 = 0.1 mol of H+
(edited 1 year ago)
Original post by booklover1313
with the sulfuric acid, H2SO4, that dissociates to 2H+ and SO42-
So for each molecule of sulfuric acid, you have 2 H+
So 1 mol of sulfuric acid will produce 2 mol H+
We only have 0.05mol of sulfuric acid in the question, and so we therefore get 0.05 x 2 = 0.1 mol of H+

Yeah but why do we need the amount of ions
Original post by Roxibox123
Yeah but why do we need the amount of ions

In neutralisation reactions (acid-base reactions) it is all to do with the ions that are reacting (H+ and OH-) as they are what react together to form water. To fully react all the acid (H+ ions), you need to add the same number of moles of base (OH- ions) to neutralise it.
Original post by AA321123
In neutralisation reactions (acid-base reactions) it is all to do with the ions that are reacting (H+ and OH-) as they are what react together to form water. To fully react all the acid (H+ ions), you need to add the same number of moles of base (OH- ions) to neutralise it.

Yes but in h2so4 does the little 2 not mean 2H+ And the little 2 in ba(oh)2
Original post by Roxibox123
Yes but in h2so4 does the little 2 not mean 2H+ And the little 2 in ba(oh)2

Yes, so
the balanced reaction between H2SO4 + Ba(OH)2 = BaSO4 + 2H2O
So if we have 0.05 mol of H2SO4, we need to react that with 0.05 mol Ba(OH)2.
50cm^3 of 1 mol dm-3 Ba(OH)2 contains: mol = vol x concentration = 50/1000 dm-3 x 1 = 0.05 mol
So there is enough Ba(OH)2 to react with all of the sulfuric acid.
So why isn't it a
Original post by Roxibox123
So why isn't it a

If you construct the equation for A, it would be:
H2SO4 + 2KOH ---> K2SO4 + 2H20

It's a 1:2 ratio

So we have 0.05 moles of H2SO4 and 0.05 x 2 = 0.1 moles of KOH so there is an excess of OH- ions.
I hope this makes sense -- it's D right?
Original post by Bookworm524
I hope this makes sense -- it's D right?

Yeah it's d x
So are we only supposed to be bothered about the reactants ... why don't we look at the products ?