Zadanie 1d
Nitric acid, HNO3, is strong, while nitrous acid, HNO2, is weak. (i) Outline the difference between a strong and a weak acid. (ii) Deduce the Lewis formula and the molecular geometry for the nitrite ion, NO2−.
Strong and weak acids and bases
Distinguish strong acids and bases (fully ionized: HCl, HNO3, H2SO4, group 1 hydroxides) from weak ones (partially ionized: organic acids, ammonia), explain that acid-base equilibria favour the weaker conjugate, and compare them experimentally by conductivity, pH and reaction rate.
Tę umiejętność sprawdza 27 zadań wzorowanych na arkuszach IB z lat 2022–2026.
Zadania sprawdzające tę umiejętność: 27 Otwórz w wyszukiwarce z filtrami
Zadanie 1a
Hydrochloric acid, HCl(aq), and hydroiodic acid, HI(aq), ionize completely in water, whereas propanoic acid, CH3CH2COOH(aq), ionizes only partly. 25.0 cm3 of 0.200 mol dm−3 HCl(aq) was titrated with sodium…
Zadanie 1b
In aqueous solution hydrogen cyanide behaves as a weak acid. (i) Write an equation for the ionization of hydrogen cyanide in water. (ii) Outline two ways in which a solution of 0.050 mol dm−3 HCN could be distinguished experimentally from…
Zadanie 25
Which solution has a pH of 11.0 at 298 K? A. 10−3 mol dm−3 KOH(aq) B. 10−11 mol dm−3 KOH(aq) C. 10−3 mol dm−3 NH3(aq) D. 10−3 mol dm−3 HCl(aq)
Zadanie 26
What is the main reason why nitric acid has a lower pH than ethanoic acid of the same concentration? A. Nitric acid is an oxidizing agent. B. Nitric acid ionizes to a greater extent in water. C. The conjugate base of nitric acid is stronger than that of…
Zadanie 2a
Methanoic acid, HCOOH(aq), and hydrochloric acid, HCl(aq), are both acids. A 0.100 mol dm−3 solution of HCOOH(aq) has a pH of 2.39 while a solution of HCl(aq) of the same concentration has a pH of 1.00. (i) Explain…
Zadanie 25
Which of these aqueous solutions has the highest pH? A. 0.10 mol dm−3 HCl B. 1.0 mol dm−3 NH3 C. 0.10 mol dm−3 KOH D. 1.0 mol dm−3 KOH
Zadanie 1e
In water, HOBr partly ionizes to give the hypobromite ion, OBr−; the ion is a much weaker sanitizer than the un-ionized acid. The graph shows how the percentages of the dissolved bromine present as HOBr(aq) and as OBr−(aq) vary with pH at 25 °C.…
- Materiał graficzny
Zadanie 1b
The structure of a tartaric acid molecule is shown. (i) State how many hydrogen atoms in a tartaric acid molecule are acidic. (ii) Deduce the structural formula of the conjugate base of tartaric acid. (iii) Predict, giving a reason, whether tartaric acid is a…
- Materiał graficzny
Zadanie 21
What is the pH of a 5.0 × 10−3 mol dm−3 aqueous solution of nitric acid, HNO3? A. 0.0050 B. 2.30 C. 3.00 D. 11.70
Zadanie 4d
Outline how 0.100 mol dm−3 solutions of ethanoic acid and nitric acid could be told apart.
Zadanie 20
Which of these species has the weakest conjugate base? A. CH3COOH B. NH4+ C. H2O D. HNO3
Zadanie 1a
Deduce the ionic equation, including state symbols, for the reaction of hydrogen bromide gas with water.
Zadanie 1c
Explain why a solution of methanoic acid has a higher pH than hydrobromic acid of the same concentration.
Zadanie 1d
A pH probe can be used to distinguish between the two acids. Identify another simple instrumental method that could be used in a school laboratory to tell them apart.
Zadanie 1e
Outline how the method identified in part 1d distinguishes between the two acids.
Zadanie 20
Which row correctly describes a weak Brønsted–Lowry acid? A. Ionizes only partially; its conjugate base is relatively strong B. Ionizes almost completely; its conjugate base is relatively strong C. Ionizes almost completely; its conjugate base is very weak D.…
Zadanie 1d
Ethanoic acid and propanone, CH3COCH3, each contain a C=O group, and their molar masses are close. (i) Considering the strongest intermolecular forces in each liquid, explain why propanone boils at a much lower temperature than ethanoic acid.…
Zadanie 1d
Ethanoic acid and propanone, CH3COCH3, both contain a carbonyl group and have similar molar masses. (i) Explain, in terms of the strongest intermolecular forces present in each liquid, why propanone boils at a much lower temperature than ethanoic acid.…
Zadanie 13
Which substance evaporates easily when pure and gives a strongly conducting solution in water? A. HBr B. KBr C. CH3Br D. NH3
Zadanie 13
Which substance is highly volatile in its pure state and gives a solution with high electrical conductivity in water? A. CH3Br B. KBr C. H2S D. HBr
Zadanie 3c
(i) Methanal can be reduced. State the name of the organic product formed. (ii) Methanal can also be oxidized to methanoic acid, HCOOH, which is a weak Brønsted–Lowry acid. State the meaning of the term weak Brønsted–Lowry acid.
Zadanie 19
Which 0.0050 mol dm−3 solution is most likely to have a pH of 12.0 at 298 K, where Kw = 1.00 × 10−14? A. Ba(OH)2(aq) B. NaOH(aq) C. NH3(aq) D. H2SO4(aq)
Zadanie 20
Which 0.10 mol dm−3 aqueous solution has the lowest pH? A. CH3COOH B. HCl C. H2SO4 D. NH4Cl
Zadanie 20
What is the strongest base in the equilibrium below? NH3 + H2O ⇌ NH4+ + OH− Kc = 3.2 × 10−7 A. NH3 B. H2O C. NH4+ D. OH−
Zadanie 19
Equal volumes of 0.050 mol dm−3 ethanoic acid and 0.050 mol dm−3 hydrochloric acid are each titrated with 0.050 mol dm−3 sodium hydroxide solution. Which quantity is the same for the two titrations? A. Initial pH…
Zadanie 20
Which acid has the weakest conjugate base? A. HF B. CH3COOH C. HNO3 D. NH4+