What is the concentration of a 25.0 mL HCl solution containing a phenolphthalein indicator that is titrated with 0.1 M NaOH if it requires 34.2 mL before the solution turns pink?

A. 0.0578 M
B. 0.137 M
C. 1.37 M
D. 0.274 M

Question

What is the concentration of a 25.0 mL HCl solution containing a phenolphthalein indicator that is titrated with 0.1 M NaOH if it requires 34.2 mL before the solution turns pink?

 		A.	0.0578 M
 		B.	0.137 M
 		C.	1.37 M
 		D.	0.274 M

vera_ewing · Answer

@JoannaBlackwelder Is it B or C?

joannablackwelder · Answer

This is a strong acid titrated with a strong base. Do you know what happens at the titration point?

vera_ewing · Answer

No @JoannaBlackwelder

anonymous · Answer

0.1M NaOH=X/l0.0342L NaOH
X is moles solute of NaOH
X= 0.0342mol NaOH
NaOH+HCl>>NaCl+H2O
0.00342 moles NaOH x (1mol HCl /1mol NaOH)=0.00342 mol HCl
0.00342mol HCl/0.025L HCl=0.137M
I think. There is a shorter way to do this, but some problem require this step, if its not balanced.

vera_ewing · Answer

Thank yo so much, @Shalante

taramgrant0543664 · Answer

@Shalante that is right good job and there is no real way other than this to do it except doing everything together in one formula

anonymous · Answer

No problem!