Monday

October 20, 2014

October 20, 2014

Posted by **casey** on Thursday, September 4, 2008 at 9:14am.

if 175 ml of KOH of unknown concentration with a methyl red indicator present is titrated with [0.275 M] H3PO4, the yellow solution turns red after 29.6 ml of the H3PO4 is added. What is the molarity of the KOH solution?

On the above problem I think it goes like this but i'm stumped...

0.172 x 27.4 / 1000 x 1/2 = Mb x 100 / 1000 ?? What do I do with the 1/2

also..

If 100 ml of HCl of unknown concentration with a methyl orange indicator present is titrated with [0.172 M] Ca(OH)2, the red solution turns yellow after 27.4 ml of the Ca(OH)2 is added, What is the molarity of the HCl solution?

Please Help I can't understand how to do this...

- chemistry -
**sammy jo**, Friday, January 7, 2011 at 10:18pmmoles H3PO4 = 0.0296 L x 0.275 M=0.00814

the balanced equation is

H3PO4 + 3 NaOH = Na3PO4 + 3 H2O

the ratio between H3PO4 and NaOH is 1 : 3

moles NaOH = 3 x 0.00814 =0.0244

molarity of NaOH = 0.0244 mol/ 0.175 L=0.140 M

**Answer this Question**

**Related Questions**

Math - one Percentage increase / decrease formula in excel that full all the ...

Math - one Percentage increase / decrease formula in excel that full all the ...

Chemistry - Dear sir, madam, I am having a little problem with the solution my ...

Chemistry - A 25.00-mL sample of an H2SO4 (2 and 4 are subscripted) solution of ...

Chemistry - A 25.00-mL sample of an H2SO4 (2 and 4 are subscripted) solution of ...

Chem - Circle the letter of the unit of mass commonly used in chemistry that ...

Math - Find the amount of money in the account at the end. $1000.00, 4 years, 7...

Calc Help - demand = (p+1)sqroot(q+1)=1000. Find elasticity of demand at a price...

Chemistry - What is the % ( m/ v) concentration of the calcium chloride solution...

PreCal - A person deposits $1000 in a bank account which pays 8% annual interest...