State an equation for the reaction of ethanoic acid with water.

Calculate the pH of ${\text{0.200 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}$ ethanoic acid $({\text{p}}{K_{\text{a}}} = 4.76)$.

Determine the pH of a solution formed from adding ${\text{50.0 c}}{{\text{m}}^{\text{3}}}$ of ${\text{1.00 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}$ ethanoic acid, ${\text{C}}{{\text{H}}_{\text{3}}}{\text{COOH(aq)}}$, to ${\text{50.0 c}}{{\text{m}}^{\text{3}}}$ of ${\text{0.600 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}$ sodium hydroxide, NaOH(aq).

(if acid added) ${\text{C}}{{\text{H}}_3}{\text{CO}}{{\text{O}}^ - } + {{\text{H}}^ + } \to {\text{C}}{{\text{H}}_3}{\text{COOH}}$;

(if alkali added) ${\text{C}}{{\text{H}}_3}{\text{COOH}} + {\text{O}}{{\text{H}}^ - } \to {\text{C}}{{\text{H}}_3}{\text{CO}}{{\text{O}}^ - } + {{\text{H}}_2}{\text{O}}$;

Explanation marks cannot be awarded without equations.

(i)     Deduce the equilibrium constant expression for this reaction.

(ii)     Explain the effect on the position of equilibrium and the value of ${K_{\text{c}}}$ when pressure is decreased and temperature is kept constant.

(iii)     2.00 mol of NOCl was placed in a ${\text{1.00 d}}{{\text{m}}^{\text{3}}}$ container and allowed to reach equilibrium at 298 K. At equilibrium, 0.200 mol of NO was present. Determine the equilibrium concentrations of NOCl and ${\text{C}}{{\text{l}}_{\text{2}}}$, and hence calculate the value of ${K_{\text{c}}}$ at this temperature.

(iv)     The value of ${K_{\text{c}}}$ is $1.60 \times {10^{ - 5}}$ at 318 K. State and explain whether the forward reaction is exothermic or endothermic.

(i)     Compare the two liquids in terms of their boiling points, enthalpies of vaporization and vapour pressures.

(ii)     Explain your answer given for part (b)(i).

Calculate the pH of a ${\text{1.50 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}$ solution of ammonia at 298 K to two decimal places, using Table 15 of the Data Booklet.

A buffer solution is made using ${\text{25.0 c}}{{\text{m}}^{\text{3}}}$ of ${\text{0.500 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}$ hydrochloric acid, HCl (aq), and ${\text{20.0 c}}{{\text{m}}^{\text{3}}}$ of ${\text{1.50 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}$ ammonia solution, ${\text{N}}{{\text{H}}_{\text{3}}}{\text{(aq)}}$.

Describe the meaning of the term buffer solution.

Determine the pH of the buffer solution at 298 K.

A ${\text{1.50 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}$ solution of ammonia is added to ${\text{25.0 c}}{{\text{m}}^{\text{3}}}$ of a ${\text{0.500 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}$ hydrochloric acid solution in a titration experiment.

Calculate the total volume of the solution at the equivalence point.

Calculate the pH of the solution at the equivalence point, using Table 15 of the Data Booklet.

Identify a suitable indicator for this titration, using Table 16 of the Data Booklet.

Define the term buffer solution.

Explain, using appropriate equations, how this solution acts as a buffer solution.

Calculate the concentration, in ${\text{mol}}\,{\text{d}}{{\text{m}}^{ - 3}}$, of sodium propanoate in this buffer solution.

The ${\text{p}}{K_{\text{a}}}$ of propanoic acid is 4.87 at 298 K.

Describe the composition of an acidic buffer solution.

Determine the pH of a buffer solution, correct to two decimal places, showing your working, consisting of 10.0 g of ${\text{C}}{{\text{H}}_{\text{3}}}{\text{COOH}}$ and 10.0 g of CH$_3$COONa in ${\text{0.250 d}}{{\text{m}}^{\text{3}}}$ of solution. ${K_{\text{a}}}$ for ${\text{C}}{{\text{H}}_{\text{3}}}{\text{COOH}} = 1.8 \times {10^{ - 5}}$ at 298 K.

(i)     State the expression for the ionic product constant of water, ${K_{\text{w}}}$.

(ii)     Explain why even a very acidic aqueous solution still has some ${\text{O}}{{\text{H}}^ - }$ ions present in it.

(iii)     State and explain the effect of increasing temperature on the value of ${K_{\text{w}}}$ given that the ionization of water is an endothermic process.

(iv)     State and explain the effect of increasing temperature on the pH of water.

(i)     Deduce the acid and conjugate base ions that make up the phosphate buffer and state the ionic equation that represents the phosphate buffer.

(ii)     Describe how the phosphate buffer minimizes the effect of the addition of a

strong base, ${\text{O}}{{\text{H}}^ - }{\text{(aq)}}$, to the buffer. Illustrate your answer with an ionic equation.

(iii)     Describe how the phosphate buffer minimizes the effect of the addition of a

strong acid, ${{\text{H}}^ + }{\text{(aq)}}$, to the buffer. Illustrate your answer with an ionic equation.

(i)     Explain why the pH of the ammonia solution is less than 13.

(ii)     Estimate the pH at the equivalence point for the titration of hydrochloric acid with ammonia and explain your reasoning.

(iii)     State the equation for the reaction of ammonia with water and write the ${K_{\text{b}}}$ expression for ${\text{N}}{{\text{H}}_{\text{3}}}{\text{(aq)}}$.

(iv)     When half the ammonia has been neutralized (the half-equivalence point), the pH of the solution is 9.25. Deduce the relationship between ${\text{[N}}{{\text{H}}_{\text{3}}}{\text{]}}$ and ${\text{[NH}}_4^ + {\text{]}}$ at the

half-equivalence point.

(v)     Determine ${\text{p}}{K_{\text{b}}}$ and ${K_{\text{b}}}$ for ammonia based on the pH at the half-equivalence point.

(vi)     Describe the significance of the half-equivalence point in terms of its effectiveness as a buffer.

(i)     Outline the difference in dissociation between strong and weak acids of the same concentration.

(ii)     Describe three tests that can be carried out in the laboratory, and the expected results, to distinguish between ${\text{0.10 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}{\text{ HCl(aq)}}$ and ${\text{0.10 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}{\text{ C}}{{\text{H}}_{\text{3}}}{\text{COOH(aq)}}$.

Calculate the pH, using table 15 of the data booklet, of a solution of ethanoic acid made by dissolving 1.40 g of the acid in distilled water to make a ${\text{500 c}}{{\text{m}}^{\text{3}}}$ solution.

Determine the pH at the equivalence point of the titration and the ${\text{p}}{K_{\text{a}}}$ of an unknown acid using the acid-base titration curve below.

Identify, using table 16 of the data booklet, a suitable indicator to show the end-point of this titration.

Describe how an indicator, that is a weak acid, works. Use Le Chatelier’s principle in your answer.

State the formula of the conjugate base of chloroethanoic acid, ${\text{C}}{{\text{H}}_{\text{2}}}{\text{ClCOOH}}$.

Identify, with a reason, whether chloroethanoic acid is weaker or stronger than ethanoic acid using table 15 of the data booklet.

Determine the pH of the solution resulting when ${\text{100 c}}{{\text{m}}^{\text{3}}}$ of ${\text{0.50 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}$ ${\text{C}}{{\text{H}}_{\text{2}}}{\text{ClCOOH}}$ is mixed with ${\text{200 c}}{{\text{m}}^{\text{3}}}$ of ${\text{0.10 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}$ NaOH.

Describe how chlorine’s position in the periodic table is related to its electron arrangement.

${\text{SC}}{{\text{l}}_{\text{2}}}$ and ${\text{SCl}}{{\text{F}}_{\text{5}}}$ are two sulfur chloride type compounds with sulfur having different oxidation states. Predict the name of the shape, the bond angle and polarity of these molecules.