Choose the answer that you think is right and then check it. Of course you may consult a Periodic Table, solubility table and the reduction potential table.
For the reaction described by the following equations:
NH4+ + OH- => NH3 + H2O
Which one of the following statements is correct?
NH4+ is behaving as an acid
NH4+ is behaving as a base
NH4+ is oxidised
NH4+ is reduced
The pH of 0.050 mol L-1 solution of hydrogen cyanide is 6.40. What percentage of the hydrogen cyanide in this solution has ionised?
4.0 x 10-7 %
8.0 x 10-6 %
4.0 x 10-5 %
8.0 x 10-4 %
Which one of the following correctly defines an acid according to the Bronsted-Lowry theory?
accepts H+ions in water
forms H+ions in water
H+ acceptor
H+ donor
A chemist carries out a titration and records the following values in the report book.
Final reading (mL)
11.6
22.00
32.41
42.07
11.47
Initial reading (mL)
0.20
11.60
22.00
32.41
1.05
What titration value should the chemist use in a subsequent calculation?
10.22
10.41
10.46
none of these
Which one of the following species cannot act as both a Bronsted-Lowry acid and base?
CH4
HCO3-
HSO4-
NH3
Pure water undergoes self-ionisation according to the equation.
2H2O (l) => H3O+(aq) + OH-(aq)
The equilibrium constant for the reactrion is:
1.0 x 10-14 at 25oC and 5.5 x 10-13 at 100oC
Which one of the following statements is correct?
At 100oC the pH of pure water is less than 7.0, but the water is still neutral
At 100oC the pH of pure water is less than 7.0, and therefore the water is acidic
At 100oC the pH of pure water is greater than 7.0, and therefore the water is basic
At 100oC the pure water is obviously still neutral and the pH must be 7.0
Which one of the following statements about 1.00 x 10-8 mol L-1 HCl is correct?
The pH is 6
The pH is a little less than 7
The pH is 8
Such a solution cannot exist
A chemist measures the pH of four 1.0 x 10-2 mol L-1 acid solutions, and obtains the following results.
Experiment
Solution
pH
1
1.0 x 10-2M CH3COOH
3.4
2
1.0 x 10-2M H3PO4
2.2
3
1.0 x 10-2M HNO3
2.0
4
1.0 x 10-2M H2SO4
1.4
Which experimental result must be incorrect?
experiment 1
experiment 2
experiment 3
experiment 4
Which one of the following groups contains only oxides that would form acids when dissolved in water?
MgO, CaO,Al2O3
MgO, Cl2O, PbO
NO2, Na2O,CO2
NO2, SO2, Cl2O
Which one of the following is most likely to be able to act as both an acid and a base?
Cl-
NH4+
OH-
O2--
When asked to list the properties of an acid-base indicator a student gave four statements (A-D).
A It must undergo an acid-base reaction
B It is easily oxidised to a coloured product
C It has acid-base conjugate forms with different colours
D It can be used to prepare a standard solution
The student`s response was not entirely correct, as only some of the statements were true. Which combination of statements is correct?
Only A and B
Only A and C
Only A and D
Only B and C
Which of the following statements best describes a neutral aqueous solution?
The concentration of H+ and OH- are equal
The pH is 7
The solution contains no basic or acidic species
The solution may contain dissolved salts
Each of the following salts is dissolved in water. Which answer correctly classifies the salts as acidic , basic or neutral?
Na2CO3 (aq) ; NH4Cl(aq) ; K3PO4(aq) ; FeCl3(aq)
neutral, acidic, basic, basic
acidic, basic, neutral, basic
basic, acidic, basic, acidic
basic, basic, acidic, acidic
When the pH of a 0.01 mol L-1 solution of sulfuric acid is measured it is found to be significantly lower than the pH of a 0.01 mol L-1 solution of phosphoric acid. What is the reason for this?
Phosphoric acid is a triprotic acid, while sulfuric acid is only diprotic, therefore the concentration of hydrogen ions is higher in the phosphoric acid solution than in the sulfuric acid solution
Phosphoric acid is a stronger acid than the sulfuric acid, so the phosphoric acid is more likely to produce hydrogen ions in solution than sulfuric acid
Sulfuric acid is a much stronger acid than phosphoric acid, so there are more hydrogen ions in the sulfuric acid solutions than the phosphoric acid solution
The sulfuric acid solution is more concentrated than the phosphoric acid soltuion, therefore there will be more hydrogen ions in the sulfuric acid solution than the phosphoric acid solution.
Consider the following three statements (I-III) about neutralisation reactions.
I A neutralisation reaction is a reaction between an acid and a base II At the equivalence point of a neutralisation reaction the pH of the resulting solution will be 7 III Salts are obtained from neutralisation reactions
Which statement or combination of statements is always correct?
Only I
Only I and II
Only I and III
I, II and III
What is the pH of 0.0050 mol L-1 solution of Ba(OH)2?
2.00
2.30
11.70
12.00
Which one of the following equations does not represent the donation and aceptance of protons?
Zn + 2 H+ <=> Zn2+ + H2
NH3 + OH- <=> NH2- + H2O
HOCl + C6H5COO- <=> OCl- + C6H5COOH
C6H5COOH + HCO3--<=> C6H5COO- +H2CO3
For the following equation
H2SO3 + H2O2 => H2SO4 + H2O
which one of the following statements is true?
Hydrogen Peroxide is actings as an acid
Hydrogen Peroxide is actings as an acid and a base
Hydrogen Peroxide is acting as an oxidising agent only
Hydrogen peroxide is acting as an oxidising and reducing agent
What is the concentration of a Ba(OH)2 solution that has a pH of 9.30?
1.00 x 10-5 mol L-1
2.00 x 10-5 mol L-1
2.50 x 10-10 mol L-1
5.01 x 10-10 mol L-1
20.0 mL of a 0.0100 mol L-1 solution of NaOH is added to 20.0 mL of a 0.0300 mol L-1 solution of NaCl. What is the pH of the resulting solution?
2.00
7.00
11.70
12.00
Which one of the following equations does not represent the donation and acceptance of protons?
2 H+ + 2 e- <=> H2
H+ + OH- <=> H2O
H2O2 + OH- <=> HO2- + H2O
H2C2O4 + CO32- <=> HC2O4-- + HCO3-
Solid sodium acetate is added to water. Which one of the following statements best describes what happens?
The pH decreases because the acetate ions react with water to produce acetic acid
The pH decreases because the sodium ions react with water to produce hydrogen ions
The pH increases because the acetate ions react with water to produce hydroxide ions
The pH increases because the sodium ions react with water to produce hydroxide ions
Ammonia is classified as a weak electrolyte. Which of the following statements best explains this?
A water solution of ammonia contains more hydroxide ions than hydrogen ions
Ammonia is very soluble in water
Hydrogen bonding exists between ammonia molecules
In a water-solution only some of the ammonia molecules have reacted with water molecules
In which one of the following will each listed compound dissolve in water to give a basic solution?
What is the pH of a 5.0 x 10-3 mol L-1 solution of barium hydroxide?
2
2.3
11.7
12
The water in a seriously neglected swimming pool is tested and found to have a pH of 3. By what factor must the hydrogen ion concentration be changed to increase the water pH to 6?
decrease the hydrogen ion concentration by 1000 times
double the hydrogen ion concentration
halve the hydrogen ion concentration
increase the hydrogen ion concentration by 1000 times
Sulfuric acid is a stronger acid than acetic (ethanoic) acid. Which one of the following statements best explains this?
Concentrated sulfuric acid has a concentration of 18 mol L-1, while concentrated acetic acid has a concentration oof 17 mol L-1
Sulfuric acid has two hydrogen atoms available for ionisation per molecule, while acetic acid has only one hydrogen atom available for ionisation per molecule
Sulfuric acid ionises to a geater extent than acetic acid
Sulfuric acid is more soluble in water than acetic acid
Which one of the following correctly identifies the acidity, basicity or neutrality of each of the given solutions?
sodium hydrogensulphate
potassium phosphate
ammonium chloride
magnesium nitrate
acidic, acidic, acidic, basic
neutral, basic, neutral, acidic
acidic, basic, acidic, neutral
basic, neutral, basic, neutral
Household vinegar can be produced by adding 250 mL of glacial (nearly pure) acetic (ethanoic) acid to 10 L of pure water. Which one of the following best describes the glacial acetic acid?