Question

A student titrates 60.0 mL of HNO3 with 0.30 M NaOH. Phenolphthalein is used as the indicator. After adding 42.2 mL of NaOH, a faint pink color change remained, and the student stops the titration. What is the molarity of HNO3?

Can someone please walk me through this? I'm not sure how to go about solving it. Thanks!

Answer 1

@aaronq :)

Answer 2

HNO3 + NaOH ---> NaNO3 + H2O
this is balanced equation, and tells about the ratio of HNO3 and NaOH i.e 1:1
so, we can use the formula:
HNO3 NaOH
C1 X V1 = C2 X V2
C1 X 60 = 0.3 X 42.2
C1 = 12.66 / 60
C1 = 0.211 M is the conc of HNO3

Answer 3

Thank you so much!

Answer 4

welcome :)