All Lewis acids contain at least one proton True False Which, if any, a buffer s

Question

All Lewis acids contain at least one proton True False Which, if any, a buffer system? CH3COOH, NaH2PO4 H2CO3, HCO3- H2PO4-, HCO3 HSO4- , HSO3- None of the above will be a buffer solution. Which of the following has the highest buffer capacity? 0.10 M H2PO4 10.10 M HPO42 0.50 M H2PO4- / 0.10 M HPCO 0.10 M H2PO4- / 0.50 M HPO42- 0.50 M H2PO4- / 0.50 M HPO42- They all have the same buffer capacity. An acetate buffer has a pH of 4.40. Which of the following changes will cause the pH to decrease? dissolving a small amount of solid sodium acetate adding a small amount of dilute hydrochloric acid adding a small amount of dilute sodium hydroxide dissolving a small amount of solid sodium chloride diluting the buffer solution with water What will be the effect of adding 0.5 mL of 0.1 M NaOH to 100 mL of an acetate buffer in which [CH3COOH] = [CH3COO-] = 0.5 M? The pH will increase slightly. The pH will increase significantly. The pH will decrease slightly. The pH will decrease significantly. Since it is a buffer solution, the pH will not be affected. What is the pH of a buffer that consists of 0.45 M CH3COOH and 0.35 M CH3COONa? Ka = 1.8 Times 10-5 4.49 4.64 4.85 5.00 5.52

Explanation / Answer

Question 10.

TRUE, typically lewis acids are elements, therefore must contain protons

Question 11.

buffer system forsm when there is a conjugate acid + weak base or conjugate base + weak acid

a) can't be, since they are not conjugates

b) this is a buffer, H2CO3 is the weak acid and _HCO3- the base

c) this is not likely to form a buffer, since no connjguates ar epresent

d) Not likely since SO4-2 and SO3-2 are not the same

choose only B

Question 12.

buffer capacity must:

ratio between species 1/1 = 1

msut have a large total value of concentration

From th elsit

The best example is D,

since 0.5/0.5 = 1

and 0.5+0.5 = 1.0 M

therefore, choose D

Q13

pH decreases as acid is added, so only B will solve this

Q14

addition of OH- will increase the pH

Q15.

pH = pKa + log(A-/HA)

pH= 4.75 + log(0.35/0.45)

pH = 4.64

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