Question

Does the pH of the solution increase, decrease, or stay the same when you add solid sodium hydrogen oxalate, NaHC₂O₄ to a dilute aqueous solution of oxalic acid, H₂C₂O₄? Explain your answer using the equation below.

H₂C₂O_{4 (aq)} + H₂O _(l)⇌ HC₂O₄^1– _(aq) + H₃O⁺ _(aq)

2)Why a solution of sodium chloride and hydrochloric acid cannot act as a buffer? (b) Propose a conjugate acid/base pair which can function as a buffer.

3)

(a) Calculate the pH of a buffer solution containing 0.300 mole of KF and 0.400 mol of HF in 1.00 liter solution. (K_a of HF is 7.2*10^–4)

(b) What will the pH of the buffer solution in question (a) be after the addition of 20.0 mL of 1.50 M NaOH.

4)In a titration experiment, 15.00 mL of 0.500 M NaOH solution neutralizes 20.00 mL of H₃PO₄ solution. What is the concentration of the H₃PO₄ solution?

5)

Consider the following data for four hypothetical acids:

acid	HA	HB	HC	HD
pKa	3.04	2.14	6.54	1.98

Which one is the strongest acid?

	1.98
		2.14
		3.04
		6.54

6)25.0 mL of 0.0200 M NH₃ is titrated with a 0.0150 M HCl. What is the pH after 40.0 mL of the HCl solution is added?

7)

25.00 mL of 0.020 M HClO is titrated with a 0.015 M NaOH. What is the pH after 20.00 mL of the NaOH solution is added? (K_a of HClO is 3.0*10^–8)

8)

Answer 1

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Kex acidic So HD is strength strongest acid. - in Sol Nha is Nhyon. - Nhat he - > NMyt + Le 2500.02 Yox 01015 05 06 - --- 0.6-0. 3 0 only In the soll, Strong Aid is present so frt is come from te. Orls 0.0015 25140 CHF) = 0.0015 ph=-dogfent) pH = - fogo.0015 Iph = 2. Naceo + h2o Acidic Buffer. 0.3 ③ H40+ Naon - 25X0-02204-0.015_- 0.5 0.3 0.5-0. 3 0 ph = pke bog sast] phapka + logo. 2002 ph = 7.53€ logies h = 7.537 0.17 pH = 7.70- Acid } Ka= 3x108 pla=_lrgka pla e log 3x10 plaz & log 3 pk = &-0.47 pke = 7.53
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