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The pH of a 0.01M solution of a weak base is 10.65. What is the value of Kb for this base?
1)2.0 x 10-5
2)5.0 x 10-4
3)5.0 x 10-20
4)0.073
The pH of a 0.55M solution of hypobromous acid, HOBr, is 4.48. Calculate the value of Ka.
1)3.0 x 104
2)2.0 x 10-9
3)6.0 x 10-5
4)3.3 x 10-5
5)1.1 x 10-9
Calculate the pH of a buffer solution prepared by dissolving 0.20 mole of cyanic acid (HCNO) and 0.80 mole of sodium cyanate (NaCNO) in enough water to make 1.0 litre of solution.
Ka(HCNO) = 2.0 x 10-4
1)0.97
2)4.30
3)3.10
4)4.40
5)3.70
What is the pH of a 0.65M sodium carbonate solution? (Kb = 1.8 x 10-4)
1)10.2
2)12
3)3.9
4)2.0
What is the pH of a 1.3M butyric acid solution? (Ka = 1.54 x 10-5)
1)4.7
2)5.0
3)2.3
4)2.5
In the reaction
HSO3- + HClO2 ↔ H2SO3 + ClO2-
The Bronsted bases are:
1)HSO3- + HClO2
2)HSO3- + ClO2-
3)H2SO3 + ClO2-
4)HClO2 + H2SO3
An indicator is weak acid (or base) having a conjugate base (or acid) with a significantly different colour. For the titration of a weak base, how would you choose an appropriate indicator?
1)Choose an indicator that has a pKb close to pKb of the base
2)Choose an indicator which changes colour anywhere in the pH range 0-7
3)Choose an indicator that has a pKa close to pKb of the base
4)Choose an indicator with a pKb close to the pH of the titration at equivalence
5)Choose an indicator with a pKa close to the pH of the titration at equivalence
An acid HA has Ka = 2.28 x 10 -4. The % ionisation of this acid in a 0.170 M solution of the acid in water is closest to
- 2.930 %
- 3.662 %
- 2.564 %
- 0.498 %
- 0.436 %
- 0.623 %
A 0.100 M solution of a weak acid, HX, has a pH of 2.610. What is the value of Ka for HX?
1)6.03 x 10 -6
2)6.03 x 10 -4
3)2.45 x 10 -2
4)2.45 x 10 -1
5)6.03 x 10 -5
6)2.45 x 10 -3
What is the pH for the solution made from 11.10 mL of 0.278 M HCl solution mixed with 70.90 mL of 0.1300 M ammonia solution? Note that the pKa for NH4+ is 9.241
1)9.24
2)8.77
3)9.54
4)9.72
5)8.94
#340153 on Dec 2023