2023 Cambridge IAS-Level Chemistry (9701) Practice Paper with Answers

A \(20\text{ cm}^3\) sample of a gaseous hydrocarbon was completely combusted in \(120\text{ cm}^3\) of oxygen (which is in excess). After cooling to room temperature and pressure, the residual gas had a volume of \(90\text{ cm}^3\). When this residual gas was passed through aqueous sodium hydroxide, the volume of gas remaining was \(50\text{ cm}^3\). What is the molecular formula of the hydrocarbon?

Which of the following changes will increase the rate of a gas-phase reaction by increasing the collision frequency of the reactant molecules without changing the activation energy or the Maxwell-Boltzmann energy distribution curve?

The table shows the standard enthalpy changes of combustion, \(\Delta H_c^\theta\), for three substances at \(298\text{ K}\). [Substance: \(C(s)\), \(\Delta H_c^\theta = -394\text{ kJ mol}^{-1}\)] [Substance: \(H_2(g)\), \(\Delta H_c^\theta = -286\text{ kJ mol}^{-1}\)] [Substance: \(CH_3OH(l)\), \(\Delta H_c^\theta = -726\text{ kJ mol}^{-1}\)]. What is the standard enthalpy change of formation of liquid methanol, \(CH_3OH(l)\), at \(298\text{ K}\) according to the equation: \(C(s) + 2H_2(g) + \frac{1}{2}O_2(g) \rightarrow CH_3OH(l)\)?

An element \(E\) in Period 3 of the Periodic Table reacts with oxygen to form two different gaseous oxides, \(G\) and \(H\). The oxidation state of \(E\) is \(+4\) in oxide \(G\) and \(+6\) in oxide \(H\). Both oxides react with water to form acidic solutions. What is element \(E\)?

An organic compound \(W\) has the molecular formula \(C_5H_{10}O\). It forms an orange-red precipitate when treated with 2,4-dinitrophenylhydrazine reagent, does not produce a silver mirror when warmed with Tollens' reagent, and does not give a yellow precipitate when treated with alkaline aqueous iodine. What is the identity of compound \(W\)?

The following dynamic equilibrium is established in a syringe at room temperature: \(2NO_2(g) \rightleftharpoons N_2O_4(g)\) (where \(NO_2\) is a brown gas and \(N_2O_4\) is a colourless gas). The plunger of the syringe is suddenly pushed in to reduce the volume of the gas mixture to half of its original volume, while the temperature is kept constant. Which statement correctly describes the initial and subsequent colour change of the gas mixture?

An organic compound \(Y\) is reacted with hot acidified \(\text{KMnO}_4\), yielding a single organic product, \(Z\). When a sample of \(Z\) is added to aqueous sodium carbonate, effervescence is observed and carbon dioxide gas is evolved. Which of the following compounds could be \(Y\)?

The successive ionisation energies of a certain Period 3 element, \(T\), are shown in the table. [1st: \(578\text{ kJ mol}^{-1}\)] [2nd: \(1817\text{ kJ mol}^{-1}\)] [3rd: \(2745\text{ kJ mol}^{-1}\)] [4th: \(11577\text{ kJ mol}^{-1}\)] [5th: \(14842\text{ kJ mol}^{-1}\)]. What is the formula of the oxide of \(T\)?

When \(10\text{ cm}^3\) of a gaseous hydrocarbon \(\text{C}_x\text{H}_y\) is completely burned in \(70\text{ cm}^3\) of oxygen (an excess), the total volume of gas remaining after combustion and cooling to room temperature is \(50\text{ cm}^3\). Passing this resulting gas mixture through aqueous sodium hydroxide reduces the volume to \(20\text{ cm}^3\). What is the molecular formula of the hydrocarbon?

The temperature of a gas mixture is increased from \(T_1\) to \(T_2\). Which statement correctly describes the changes to the Maxwell-Boltzmann distribution curve of molecular kinetic energies and the reaction rate?

Using the standard enthalpy changes of combustion given below, what is the standard enthalpy change of formation of liquid ethanol, \(\text{C}_2\text{H}_5\text{OH}(l)\)?

- \(\Delta H_c^\theta [\text{C}(s)] = -394\text{ kJ mol}^{-1}\)
- \(\Delta H_c^\theta [\text{H}_2(g)] = -286\text{ kJ mol}^{-1}\)
- \(\Delta H_c^\theta [\text{C}_2\text{H}_5\text{OH}(l)] = -1367\text{ kJ mol}^{-1}\)

Three Period 3 oxides are added separately to excess water. Which row correctly describes the pH of the resulting mixtures at \(25^\circ\text{C}\)?

An organic compound **X** has the molecular formula \(\text{C}_4\text{H}_8\text{O}\). **X** reacts with 2,4-dinitrophenylhydrazine reagent to form an orange precipitate, but it does not produce a red precipitate when heated with Fehling's solution. Which structure is a possible isomer of **X**?

For the following dynamic equilibrium:

\(2\text{A}(g) + \text{B}(g) \rightleftharpoons 2\text{C}(g) \quad \Delta H = -92\text{ kJ mol}^{-1}\)

Which change will increase the numerical value of the equilibrium constant, \(K_c\)?

An organic compound **Y** with the molecular formula \(\text{C}_4\text{H}_{10}\text{O}_2\) contains two hydroxyl groups. When **Y** is heated under reflux with an excess of acidified potassium dichromate(VI), the organic product formed is a diketone. Which diol is compound **Y**?

Equal amounts of four different halogenoalkanes are added to separate test tubes containing aqueous silver nitrate in ethanol at \(50^\circ\text{C}\). Which halogenoalkane will form a precipitate the fastest?

An alloy containing only zinc and copper has a mass of 2.00 g. When this sample is treated with an excess of dilute hydrochloric acid, only the zinc reacts, producing \(540\text{ cm}^3\) of hydrogen gas measured at room temperature and pressure (r.t.p.).

What is the percentage by mass of copper in the alloy?
[Molar volume of a gas at r.t.p. = \(24.0\text{ dm}^3\text{ mol}^{-1}\); \(A_r\text{ (Zn) = 65.4}\); \(A_r\text{ (Cu) = 63.5}\)]

For many reactions, a modest rise in temperature of 10 K can approximately double the rate of reaction.

Which statement describes the main reason for this observation?

Hydrazine, \(N_2H_4(l)\), undergoes combustion according to the equation below:

\(N_2H_4(l) + O_2(g) \rightarrow N_2(g) + 2H_2O(l) \quad \Delta H_c^\ominus = -622\text{ kJ mol}^{-1}\)

The standard enthalpy change of formation of liquid water, \(\Delta H_f^\ominus [H_2O(l)]\), is \(-286\text{ kJ mol}^{-1}\).

What is the standard enthalpy change of formation of liquid hydrazine, \(\Delta H_f^\ominus [N_2H_4(l)]\)?

An oxide of a Period 3 element, \(X\), is a solid at room temperature and pressure. When a sample of this oxide is added to water, it reacts vigorously to form a strongly acidic solution.

What is element \(X\)?

An organic compound, \(Y\), reacts with 2,4-dinitrophenylhydrazine reagent to form an orange-red precipitate. However, \(Y\) does not produce a silver mirror when warmed with Tollens' reagent.

Which compound could be \(Y\)?

Consider the reversible reaction involved in the Contact process:

\(2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g) \quad \Delta H = -197\text{ kJ mol}^{-1}\)

Which change will increase the equilibrium yield of sulfur trioxide, \(SO_3(g)\), but leave the value of the equilibrium constant, \(K_c\), unchanged?

A gaseous hydrocarbon, \(W\), has a relative molecular mass of 70.0. When a sample of \(W\) is completely burned in excess oxygen, the volume of carbon dioxide gas produced is exactly five times the volume of hydrocarbon \(W\) burned, with both gas volumes measured under the same conditions of temperature and pressure.

What is the molecular formula of hydrocarbon \(W\)?
[\(A_r\text{ (C) = 12.0}\); \(A_r\text{ (H) = 1.0}\)]

The reaction between peroxodisulfate ions, \(S_2O_8^{2-}\), and iodide ions, \(I^-\), is catalyzed by iron(III) ions, \(Fe^{3+}\):

\(S_2O_8^{2-}(aq) + 2I^-(aq) \xrightarrow{Fe^{3+}} 2SO_4^{2-}(aq) + I_2(aq)\)

Which statement correctly describes a feature of this catalyzed reaction?

A \(20.0\text{ cm}^3\) sample of a gaseous hydrocarbon, \(C_xH_y\), was mixed with excess oxygen and exploded. After cooling to room temperature, the decrease in volume of the gas mixture was found to be \(50.0\text{ cm}^3\). When the remaining gas was shaken with excess aqueous sodium hydroxide, there was a further contraction in volume of \(40.0\text{ cm}^3\). What is the molecular formula of the hydrocarbon?

For a gaseous reaction, the temperature is increased from \(T_1\) to \(T_2\). Which statement correctly describes the changes in the Maxwell-Boltzmann distribution curve and the reaction rate?

The standard enthalpies of combustion, \(\Delta H_c^\theta\), of carbon (graphite), hydrogen gas, and liquid propan-1-ol, \(C_3H_7OH(l)\), are \(-394\text{ kJ mol}^{-1}\), \(-286\text{ kJ mol}^{-1}\), and \(-2021\text{ kJ mol}^{-1}\) respectively. What is the standard enthalpy change of formation, \(\Delta H_f^\theta\), of liquid propan-1-ol?

An element \(X\) in Period 3 of the Periodic Table forms an oxide \(X_2O_3\). Which statement about this oxide and the element \(X\) is correct?

An organic compound \(Y\) is treated with HCN in the presence of NaCN. The resulting product is then heated under reflux with dilute hydrochloric acid to yield 2-hydroxy-2-methylbutanoic acid. What is the structure of the starting compound \(Y\)?

In an experiment, \(2.00\text{ mol}\) of nitrogen dioxide, \(NO_2(g)\), is placed in a sealed \(1.00\text{ dm}^3\) flask at a constant temperature. The \(NO_2(g)\) dimerises to form dinitrogen tetroxide, \(N_2O_4(g)\), according to the equation: \(2NO_2(g) \rightleftharpoons N_2O_4(g)\). At equilibrium, the flask contains \(0.60\text{ mol}\) of \(N_2O_4(g)\). What is the value of the equilibrium constant, \(K_c\), at this temperature?

Which molecule or ion has both a bond angle of less than \(109.5^\circ\) and a non-linear shape?

An alcohol with the molecular formula \(C_4H_{10}O\) is heated under reflux with acidified potassium dichromate(VI) to form an organic product \(Z\). Product \(Z\) reacts with alkaline aqueous iodine to form a yellow precipitate. Which alcohol is it?

A mixture of methane (\(\text{CH}_4\)) and propane (\(\text{C}_3\text{H}_8\)) with a total volume of \(40\text{ cm}^3\) is completely combusted in excess oxygen. The total volume of gaseous products, measured at a high temperature where water is entirely in the gaseous state, is \(180\text{ cm}^3\). All gas volumes are measured at the same temperature and pressure.

What is the volume of propane in the original mixture?

A chemical reaction is carried out at temperature \(T_1\). The temperature is then increased to \(T_2\).

Which statement correctly explains the increase in the rate of reaction at the higher temperature, \(T_2\)?

The standard enthalpy changes of combustion, \(\Delta H_c^\ominus\), for carbon, hydrogen, and propan-1-ol are given in the table.

$$\begin{array}{|c|c|}
\hline
\text{Substance} & \Delta H_c^\ominus / \text{kJ mol}^{-1} \\
\hline
\text{C}(s) & -394 \\
\text{H}_2(g) & -286 \\
\text{CH}_3\text{CH}_2\text{CH}_2\text{OH}(l) & -2021 \\
\hline
\end{array}$$

What is the standard enthalpy change of formation, \(\Delta H_f^\ominus\), of propan-1-ol, \(\text{CH}_3\text{CH}_2\text{CH}_2\text{OH}(l)\)?

An element, \(X\), is in Period 3 of the Periodic Table. It forms an oxide, \(X_2\text{O}_3\), which is amphoteric.

Which statement about element \(X\) and its compounds is correct?

An organic compound \(Y\) has the molecular formula \(\text{C}_4\text{H}_8\text{O}\).

\(Y\) reacts with 2,4-dinitrophenylhydrazine reagent to form an orange precipitate, but does not give a silver mirror when warmed with Tollens' reagent.

Which product is formed when \(Y\) is reduced using \(\text{NaBH}_4\)?

A sample of anhydrous magnesium nitrate, \(\text{Mg(NO}_3)_2\), has a mass of \(7.42\text{ g}\).

How many total ions (cations and anions) are present in this sample?

[Assume the Avogadro constant, \(L = 6.02 \times 10^{23}\text{ mol}^{-1}\); \(M_r\) of \(\text{Mg(NO}_3)_2 = 148.3\)]

Which statement correctly describes a heterogeneous catalyst in a reaction?

Some average bond energies are given in the table.

$$\begin{array}{|c|c|}
\hline
\text{Bond} & \text{Average bond energy} / \text{kJ mol}^{-1} \\
\hline
\text{C}-\text{H} & 413 \\
\text{C}-\text{Cl} & 346 \\
\text{H}-\text{Cl} & 432 \\
\text{Cl}-\text{Cl} & 242 \\
\hline
\end{array}$$

The reaction between methane and chlorine to form chloromethane is shown.

$$\text{CH}_4(g) + \text{Cl}_2(g) \rightarrow \text{CH}_3\text{Cl}(g) + \text{HCl}(g)$$

What is the enthalpy change, \(\Delta H\), for this reaction?

An alloy of zinc and copper has a mass of 2.45 g. When this alloy sample is reacted with an excess of dilute hydrochloric acid, only the zinc reacts, producing zinc chloride and hydrogen gas:

$$\text{Zn(s)} + 2\text{HCl(aq)} \rightarrow \text{ZnCl}_2\text{(aq)} + \text{H}_2\text{(g)}$$

The hydrogen gas produced is collected and its volume is measured as $685\text{ cm}^3$ at a temperature of $20\text{ }^\circ\text{C}$ and a pressure of $101\text{ kPa}$.

(a) Define the term relative atomic mass.
(b) Use the ideal gas equation, $pV = nRT$, to calculate the number of moles of hydrogen gas collected. Give your answer to 3 significant figures. [$R = 8.31\text{ J K}^{-1}\text{ mol}^{-1}$]
(c) Deduce the number of moles of zinc that reacted, and calculate the mass of zinc in the sample. [$A_r$: $\text{Zn} = 65.4$]
(d) Calculate the percentage by mass of copper in the alloy sample.
(e) Write the ionic equation, including state symbols, for the reaction of zinc with dilute hydrochloric acid.

(a) The reaction between peroxodisulfate ions, $\text{S}_2\text{O}_8^{2-}$, and iodide ions, $\text{I}^-$, is catalysed by $\text{Fe}^{3+}$(aq) ions.

(i) State why this reaction is very slow in the absence of a catalyst.
(ii) Explain why $\text{Fe}^{3+}$(aq) acts as a homogeneous catalyst in this reaction.
(iii) Write two ionic equations to show how $\text{Fe}^{3+}$(aq) catalyses this reaction.

(b) The decomposition of ammonia on a hot tungsten surface is an example of heterogeneous catalysis.

(i) Describe the general mechanism of heterogeneous catalysis on a solid surface.
(ii) Describe the Maxwell–Boltzmann distribution of molecular energies and explain how a catalyst increases the rate of reaction. In your answer, refer to the relative positions of the uncatalysed activation energy ($E_{\text{a, uncatalysed}}$) and the catalysed activation energy ($E_{\text{a, catalysed}}$).

(a) Define standard enthalpy change of formation, $\Delta H_{\text{f}}^\ominus$.
(b) Write the chemical equation for the reaction representing the standard enthalpy change of formation of liquid propan-1-ol, $\text{C}_3\text{H}_7\text{OH(l)}$. Include state symbols.
(c) The standard enthalpy changes of combustion, $\Delta H_{\text{c}}^\ominus$, for carbon, hydrogen, and propan-1-ol are given below:
- $\Delta H_{\text{c}}^\ominus[\text{C(s, graphite)}] = -394\text{ kJ mol}^{-1}$
- $\Delta H_{\text{c}}^\ominus[\text{H}_2\text{(g)}] = -286\text{ kJ mol}^{-1}$
- $\Delta H_{\text{c}}^\ominus[\text{C}_3\text{H}_7\text{OH(l)}] = -2021\text{ kJ mol}^{-1}$

(i) State Hess's Law and construct an enthalpy cycle to relate these values to the enthalpy of formation of propan-1-ol.
(ii) Calculate the standard enthalpy change of formation of liquid propan-1-ol. Show your working.
(d) Explain why the experimental value of the enthalpy change of combustion of propan-1-ol determined using a simple laboratory calorimeter is usually less exothermic than the theoretical value.

(a) Phosphorus(V) chloride, $\text{PCl}_5$, and silicon(IV) chloride, $\text{SiCl}_4$, both react vigorously with water.

(i) Write a balanced chemical equation for the reaction of $\text{SiCl}_4$ with water.
(ii) State the approximate pH of the resulting solution when $\text{PCl}_5$ reacts with excess water. Explain this observation by identifying the species responsible for the acidity.

(b) Period 3 oxides show a trend from basic to acidic behavior across the period.

(i) Contrast the structures and bonding of sodium oxide, $\text{Na}_2\text{O}$, and sulfur trioxide, $\text{SO}_3$.
(ii) Describe what is observed when a sample of solid $\text{Na}_2\text{O}$ is added to water, and write an equation for the reaction.
(iii) Write a balanced chemical equation for the reaction of aluminium oxide, $\text{Al}_2\text{O}_3$, with hot aqueous sodium hydroxide, and state the term used to describe this type of oxide behavior.

(a) Propanal and propanone are structural isomers with the molecular formula $\text{C}_3\text{H}_6\text{O}$.

(i) State the type of structural isomerism shown by these two compounds.
(ii) Describe a chemical test, including reagents and observations, that can be used to distinguish propanal from propanone.

(b) Propanal reacts with hydrogen cyanide, $\text{HCN}$, in the presence of a sodium cyanide, $\text{NaCN}$, catalyst to form 2-hydroxybutanenitrile.

(i) Write the mechanism for this nucleophilic addition reaction. Show all relevant lone pairs, dipoles, and curly arrows.
(ii) Explain why the product 2-hydroxybutanenitrile is formed as a racemic mixture of optical isomers.

(c) Identify the reagent and conditions required to reduce propanone to propan-2-ol.

Methanol is synthesised industrially by the reversible reaction of carbon monoxide with hydrogen in the presence of a catalyst:

$$\text{CO(g)} + 2\text{H}_2\text{(g)} \rightleftharpoons \text{CH}_3\text{OH(g)} \quad \Delta H = -91\text{ kJ mol}^{-1}$$

(a) State two features of a system in dynamic equilibrium.
(b) Write an expression for the equilibrium constant, $K_c$, for this reaction, and state its units.
(c) In an experiment, $1.20\text{ mol}$ of $\text{CO}$ and $2.20\text{ mol}$ of $\text{H}_2$ are placed in a sealed container of volume $5.00\text{ dm}^3$ at a constant temperature. When equilibrium is reached, the mixture contains $0.40\text{ mol}$ of $\text{CH}_3\text{OH}$.

(i) Calculate the equilibrium amounts, in moles, of $\text{CO}$ and $\text{H}_2$.
(ii) Calculate the value of $K_c$ at this temperature. Show your working and include units.

(d) State and explain the effect of increasing the temperature on the yield of methanol, $\text{CH}_3\text{OH}$, at equilibrium.

In this experiment, you will determine the value of \(x\) in hydrated sodium carbonate, \(\text{Na}_2\text{CO}_3 \cdot x\text{H}_2\text{O}\). You are provided with: **FB 1**: Hydrated sodium carbonate, \(\text{Na}_2\text{CO}_3 \cdot x\text{H}_2\text{O}\) (solid); **FB 2**: \(0.100\text{ mol dm}^{-3}\) hydrochloric acid, \(\text{HCl}\); Methyl orange indicator. **Procedure:** 1. Weigh the container with **FB 1** and record its mass. 2. Dissolve all the **FB 1** in about \(100\text{ cm}^3\) of distilled water in a beaker. 3. Transfer the solution quantitatively to a \(250.0\text{ cm}^3\) volumetric flask, make up to the mark with distilled water, and mix thoroughly. Label this solution **FB 3**. 4. Fill a burette with **FB 2**. 5. Pipette a \(25.0\text{ cm}^3\) portion of **FB 3** into a conical flask. 6. Add a few drops of methyl orange indicator. 7. Titrate the solution in the flask with **FB 2** until the end-point is reached. 8. Repeat the titration as many times as necessary to obtain concordant results. **Sample Results:** For the purpose of the calculations in parts (b) to (c), use the following sample data: Mass of container + **FB 1** = \(14.82\text{ g}\); Mass of empty container = \(11.24\text{ g}\); Mean volume of **FB 2** used = \(25.00\text{ cm}^3\). **Questions:** (a) Prepare a results table showing all titration details. (b) (i) Calculate the amount, in moles, of \(\text{HCl}\) present in the mean volume of **FB 2** used. (ii) Using the equation: \(\text{Na}_2\text{CO}_3(\text{aq}) + 2\text{HCl}(\text{aq}) \rightarrow 2\text{NaCl}(\text{aq}) + \text{CO}_2(\text{g}) + \text{H}_2\text{O}(\text{l})\), calculate the amount, in moles, of sodium carbonate present in the \(25.0\text{ cm}^3\) portion of **FB 3** pipetted. (iii) Calculate the amount, in moles, of sodium carbonate present in the \(250.0\text{ cm}^3\) volumetric flask. (iv) Calculate the relative formula mass, \(M_{\text{r}}\), of the hydrated sodium carbonate, \(\text{Na}_2\text{CO}_3 \cdot x\text{H}_2\text{O}\). (v) Determine the value of \(x\) to the nearest integer. (c) (i) Each weighing on the balance used has an uncertainty of \(\pm 0.01\text{ g}\). Calculate the maximum percentage uncertainty in the mass of **FB 1** used. (ii) Suggest one modification to the titration method, other than repeating the titration, that would reduce the percentage uncertainty in the volume of the titre.

In this experiment, you will investigate how the concentration of sodium thiosulfate affects the rate of its reaction with hydrochloric acid.

The equation for the reaction is:
\[\text{Na}_2\text{S}_2\text{O}_3\text{(aq)} + 2\text{HCl(aq)} \rightarrow 2\text{NaCl(aq)} + \text{S(s)} + \text{SO}_2\text{(g)} + \text{H}_2\text{O(l)}\]

You are provided with:
* \text{FA 1}: \(0.10\text{ mol dm}^{-3}\) sodium thiosulfate solution
* \text{FA 2}: \(2.0\text{ mol dm}^{-3}\) hydrochloric acid
* Distilled water

**Method:**
1. Draw a dark black cross on a piece of white paper and place a \(250\text{ cm}^3\) conical flask directly over the cross.
2. Add \(50.0\text{ cm}^3\) of \text{FA 1} to the flask.
3. Measure \(10.0\text{ cm}^3\) of \text{FA 2} using a measuring cylinder.
4. Add the \text{FA 2} to the flask, immediately start a stopclock, and swirl the mixture once to mix.
5. Look down vertically through the mouth of the flask at the cross. Record the time, \(t\), in seconds, taken for the cross to become completely obscured by the sulfur precipitate.
6. Empty, thoroughly rinse, and dry the flask.
7. Repeat the experiment using different mixtures of \text{FA 1} and distilled water to make a total volume of \(50.0\text{ cm}^3\) of thiosulfate solution. In each run, keep the volume of \text{FA 2} constant at \(10.0\text{ cm}^3\). Carry out four further experiments using different concentrations of \text{FA 1}.

**(a)** Record your results in a single, clearly structured table. Include columns for the volume of \text{FA 1}, volume of water, time \(t\), and the rate represented by \(1/t\) (calculated to 3 significant figures with appropriate units).

**(b)** Plot a graph of \(1/t\) (y-axis) against the volume of \text{FA 1} (x-axis) on a grid. Draw a line of best fit.

**(c)** (i) Using your graph, describe the relationship between the concentration of sodium thiosulfate and the rate of reaction.
(ii) Deduce the order of reaction with respect to sodium thiosulfate, justifying your answer.
(iii) State how the rate of reaction would change if the concentration of \text{FA 2} (hydrochloric acid) was doubled, assuming the reaction is zero-order with respect to \text{HCl}.

**(d)** (i) State one significant source of experimental error in this method that arises from the observation of the cross.
(ii) Suggest a specific improvement to the apparatus or method to minimize this source of error.

You are provided with two aqueous solutions, FA 1 and FA 2. Each solution contains one cation and one anion from the list in the Qualitative Analysis Notes.

(a) Carry out the following tests on FA 1 and record your observations in a single, clearly structured table. Include tests with aqueous sodium hydroxide, aqueous ammonia, and aqueous silver nitrate followed by dilute aqueous ammonia.

Identify the cation and anion present in FA 1. Support your identifications with reasoning from your observations.

(b) Carry out the following tests on FA 2 and record your observations:
- Test 1: To a 1 cm depth of FA 2 in a boiling tube, add 1 cm depth of aqueous sodium hydroxide, \(\text{NaOH}\). Warm the mixture gently and test any gas evolved with damp red litmus paper.
- Test 2: To a 1 cm depth of FA 2 in a test-tube, add 1 cm depth of aqueous barium nitrate, followed by 1 cm depth of dilute nitric acid.

Identify the cation and anion present in FA 2.

(c) Describe a chemical test that would allow you to distinguish between aqueous solutions containing sulfite, \(\text{SO}_3^{2-}\), and sulfate, \(\text{SO}_4^{2-}\) ions. State the reagents you would use and the expected observations for each ion.