WorksheetsPREPSPM CHAP 7
Total questions: 12
Worksheet time: 50mins
NAMA
CLASS
What is the expected colour when S, T and U are added separately into a solution with a pH of
9.52 ?
S: yellow T:blue U: light pink
S: red T:yellow U: colourless
S: yellow T:blue U: pink
S: orange T:green U: light pink
Choose the arrangement of the conjugate bases of the following weak acids in order of increasing strength of basicity.
CN−< OBr−< OCl−< NO2−
OBr−< OCl−< NO2− < CN−
OCl− < OBr−< NO2− < CN−
NO2− < OCl− < OBr− < CN−
Choose the CORRECT statement about 0.1 M ethylamine, CH3CH2NH2
[Kb = 5.6 x 10−4]
Its pH is 13
Concentration of OH− is 7.21 x 10−3 M.
The base ionized completely in aqueous solution.
The dissociation of ethylamine is 0.36%.
What is the initial concentration of a solution of pyridine, C5H5N which pH is 11.22? [Kb for C5H5N = 6.3 x 10-6]
0.15
0.35
0.44
0.50
A buffer solution contains a mixture of sodium ethanoate and ethanoic acid. The addition of 1 cm3 of 1.0 mol dm-3 HCI will
I. increase the concentration of ethanoic acid in the buffer solution
II. decrease the concentration of ethanoate ions in the buffer solution
III. increase the pH of the buffer solution
I only
I & II only
II & III only
I,II & III
The pH of a saturated solution of strontium hydroxide, Sr(OH)2 is 10.52.
Calculate the solubility product, Ksp for Sr(OH)2.
1.66 x 10 -11
1.75 x 10 -11
1.82 x 10 -11
1.92 x 10 -11
Calculate the pH of a 0.1 M solution of acetic acid. Given Ka= 1.85 x 10-5.
2.6
2.9
2.4
11.6
The pH of a weak monoprotic acid is 4.0 if its concentration is 0.01 mol dm-3. What is the pKa value for this acid ?
4.0
5.0
6.0
6.5
The pH of a buffer system containing 1.0M CH3COOH and 1.0 M CH3COONa is 4.91. Calculate the pH after addition of 0.10 mole of gaseous HCl to 1L of the solution by assuming the volume of solution does not change when HCl is added.
[Ka for CH3COOH = 1.8 x 10-5]
4.90
4.66
4.83
4.92
Calculate the solubility of magnesium phosphate, Mg3(PO4)2, in g L-1.
[Ksp Mg3(PO4)2 = 5.2 x 10-24,
Molar mass Mg3(PO4)2 = 262 g mol-1]
3.28 x 10-8 gL-1
1.22 x 10-9 gL-1
1.78 x 10-3 gL-1
2.26×10-3g L-1
