titration q

[inaccensa]

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If calcium hydroxide dissolved in NaOH and is being titrated by HCl, it will still have the equivalence pt at pH 7? I'm just confused since there are 3 moles of hydroxide ions, if it does indeed neutralize at pH 7, then there must be 3 equvivalence pts on the graph or 2?

 

[loveoforganic]

It's just more strong base. It will take 1.5 equivs of equimolar HCl to titrate a 50/50 NaOH / CaOH soln. The graph will follow a normal strong acid/base titration curve.

 

[Tokspor]

It's just more strong base. It will take 1.5 equivs of equimolar HCl to titrate a 50/50 NaOH / CaOH soln. The graph will follow a normal strong acid/base titration curve.

How did you get the 50/50 value?

 

[loveoforganic]

Calcium hydroxide donates two hydroxides, sodium hydroxide donates one. If they're present in equimolar concentrations, you have an average of 1.5 moles hydroxide per mole solute.

 

[inaccensa]

Calcium hydroxide donates two hydroxides, sodium hydroxide donates one. If they're present in equimolar concentrations, you have an average of 1.5 moles hydroxide per mole solute.

Can you please explain that. Are you saying that we'll use 2 moles of solute?

 

[loveoforganic]

2 molar equivalents of HCl

 

[inaccensa]

2 molar equivalents of HCl

Aren't there 3 moles of OH-? Why are you calculating 1.5 moles/ mole solute?
Shouldn't we use 3 moles of HCl?

 

[loveoforganic]

You said you have calcium hydroxide dissolved in sodium hydroxide. I'm assuming you meant an equivalent mixture. (2 hydroxides + 1 hydroxide) / (1 solution + 1 solution) = 3/2 = 1.5

 

[inaccensa]

You said you have calcium hydroxide dissolved in sodium hydroxide. I'm assuming you meant an equivalent mixture. (2 hydroxides + 1 hydroxide) / (1 solution + 1 solution) = 3/2 = 1.5

Honestly, I don't know whether its an equivalent mixture,since the passage didn't say anything. nevertheless, i still don't understand your pt. I can see where you are getting the 1.5, but what does this mean in terms of titration. Sorry for being such a pain. But i'm really not getting this concept.😳

 

[Isoprop]

Equiv point is when the amount of acid added is equal to the amount of base in the solution.

Thus, the only players left in the solution are CaCl2 and NaCl. The pH of this solution is 7.

 

[loveoforganic]

Honestly, I don't know whether its an equivalent mixture,since the passage didn't say anything. nevertheless, i still don't understand your pt. I can see where you are getting the 1.5, but what does this mean in terms of titration. Sorry for being such a pain. But i'm really not getting this concept.😳

If you have 1.5 hydroxides, you need 1.5 H+'s.

 

[zmatrix]

If calcium hydroxide dissolved in NaOH and is being titrated by HCl, it will still have the equivalence pt at pH 7? I'm just confused since there are 3 moles of hydroxide ions, if it does indeed neutralize at pH 7, then there must be 3 equvivalence pts on the graph or 2?

To answer your questions:
Yes, equivalence of strong acid/strong base titration occurs at pH 7.

There is only 1 equivalence point on the graph at pH 7.

Loveoforganic is referring to the fact that Calcium Hydroxide = Ca(OH)2 since Calcium is a 2+ cation (Ca++). So every mol of Ca(OH)2 produces 2 mols of hydroxide ions.