Question

In: Chemistry

What volume (to the nearest 0.1 mL) of 5.20-M NaOH must be added to 0.500 L...

What volume (to the nearest 0.1 mL) of 5.20-M NaOH must be added to 0.500 L of 0.350-M HNO2 to prepare a pH = 3.50 buffer?

Solutions

Expert Solution

OH- + HNO2NO2- + H2O

this neutraization reaction happens in the soution,when strong base NaOH is completely used up.

moles of NaOH=5.20 M*V   [v=required volume]

moles of HNO2=0.35 mol/L*0.5L=0.17 mol

ICE table

                                [OH-]             [ HNO2]     [NO2-]

initial                        5.20*V             0.17        0

change                       -5.20V          -0.520V      +0.520V

equilibrium                 0.0    0.17-0.520V      0.520V


using henderson-hasselbach equation, you can calculate the [Base]/[acid] =[NO2-]/[HNO2] needed to get a pH=3.50 with the buffer. NaNO2/HNO2

pH=pka+log [NO2-]/[HNO2]

pka for NaNO2/HNO2 buffer=3.40

plug in the values,

3.50=3.40+log [NO2-]/[HNO2]

0.10=log [NO2-]/[HNO2]

[NO2-]/[HNO2]=10^0.10=1.26

or,

[NO2-]/[HNO2]=1.26

0.520V/( 0.17-0.520V)=1.26

or,0.520V=0.214-0.655V

1.175V=0.214

V=0.182 L=18.2 ml

volume of NaOH=18.2 ml


Related Solutions

What volume (to the nearest 0.1 mL) of 5.30-M NaOH must be added to 0.700 L...
What volume (to the nearest 0.1 mL) of 5.30-M NaOH must be added to 0.700 L of 0.350-M HNO2 to prepare a pH = 3.70 buffer? What volume (to the nearest 0.1 mL) of 4.80-M HCl must be added to 0.550 L of 0.250-M K2HPO4 to prepare a pH = 8.00 buffer?
What volume (to the nearest 0.1 mL) of 6.00-M NaOH must be added to 0.400 L...
What volume (to the nearest 0.1 mL) of 6.00-M NaOH must be added to 0.400 L of 0.250-M HNO2 to prepare a pH = 4.30 buffer? What volume (to the nearest 0.1 mL) of 5.50-M HCl must be added to 0.250 L of 0.200-M K2HPO4 to prepare a pH = 7.10 buffer?
a.) What volume (to the nearest 0.1 mL) of 4.50-M NaOH must be added to 0.300...
a.) What volume (to the nearest 0.1 mL) of 4.50-M NaOH must be added to 0.300 L of 0.150-M HNO2 to prepare a pH = 3.20 buffer? ______ mL b.) What volume (to the nearest 0.1 mL) of 4.00-M HCl must be added to 0.700 L of 0.350-M K2HPO4 to prepare a pH = 7.50 buffer? _______ mL
What volume (to the nearest 0.1 mL) of 7.10-M HCl must be added to 0.550 L...
What volume (to the nearest 0.1 mL) of 7.10-M HCl must be added to 0.550 L of 0.350-M K2HPO4 to prepare a pH = 7.50 buffer?
1a)What volume (to the nearest 0.1 mL) of 7.10-M HCl must be added to 0.550 L...
1a)What volume (to the nearest 0.1 mL) of 7.10-M HCl must be added to 0.550 L of 0.350-M K2HPO4 to prepare a pH = 7.50 buffer? b)What volume (to the nearest 0.1 mL) of 7.60-M NaOH must be added to 0.700 L of 0.200-M HNO2 to prepare a pH = 3.20 buffer? c)How many mL (to the nearest mL) of 0.250-M KF solution should be added to 740. mL of 0.220-M HF to prepare a pH = 3.10 solution? b)What...
a) What volume (to the nearest 0.1 mL) of 6.60-M HCl must be added to 0.450...
a) What volume (to the nearest 0.1 mL) of 6.60-M HCl must be added to 0.450 L of 0.200-M K2HPO4 to prepare a pH = 7.40 buffer? b) What volume (to the nearest 0.1 mL) of 7.10-M NaOH must be added to 0.600 L of 0.250-M HNO2 to prepare a pH = 3.10 buffer?
What volume of a 0.1 M NaOH solution must be combined with 25 mL of 0.2...
What volume of a 0.1 M NaOH solution must be combined with 25 mL of 0.2 M HNO3 to reach a pH of 11.5?
calculate the volume of 0.500 M NaOH which must be added to 2.25g of phosphoric acid...
calculate the volume of 0.500 M NaOH which must be added to 2.25g of phosphoric acid (formula weight 98.00g/mol) to yield a buffer of pH= 6.70 when diluted to one liter. Given acid dissociation for H3PO4 are : pka1= 2.14, pka2= 7.20, pka3 = 12.10
Calculate the volume (in mL) of 0.170 M NaOH that must be added to 259 mL...
Calculate the volume (in mL) of 0.170 M NaOH that must be added to 259 mL of 0.0419 M 3-(N-Morpholino)propanesulfonic acid (MOPS) to give the solution a pH of 7.55. The pKa of MOPS = 7.18.
a) Calculate the volume (in ML) of 0.170 M NaOH that must be added to 365...
a) Calculate the volume (in ML) of 0.170 M NaOH that must be added to 365 mL of 0.0515 M 3-(N-Morpholino) propanesulfonic acid (MOPS) to give the solution a pH of 7.55. The pKa of MOPS =7.18. b) A buffer with a pH of 4.24 contains 0.11 M of sodium benzoate and 0.10 M of benzoic acid. What is the concentration of [H+] in the solution after the addition of 0.056 mol of HCl to a final volume of 1.6...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT