Which of the following processes does NOT involve oxidation or reduction?
- A.Reaction of chlorine with cold sodium hydroxide solution.
- B.Action of concentrated sulfuric acid on sodium chloride.
- C.Thermal decomposition of copper(II) nitrate.
- D.Action of hot concentrated nitric acid on carbon.
Given the following standard enthalpy changes of combustion (\(\Delta H_c^\theta\)): Carbon, \(\text{C(s, graphite)} = -393.5\text{ kJ mol}^{-1}\); Hydrogen, \(\text{H}_2\text{(g)} = -285.8\text{ kJ mol}^{-1}\); Ethanol, \(\text{C}_2\text{H}_5\text{OH(l)} = -1367.3\text{ kJ mol}^{-1}\). What is the standard enthalpy change of formation of ethanol (\(\text{C}_2\text{H}_5\text{OH(l)}\))?
- A.\(-277.1\text{ kJ mol}^{-1}\)
- B.\(+277.1\text{ kJ mol}^{-1}\)
- C.\(-688.0\text{ kJ mol}^{-1}\)
- D.\(+688.0\text{ kJ mol}^{-1}\)
Which of the following combinations of reagents and conditions is most suitable for converting propan-1-ol to propan-2-ol?
- A.Step 1: Heat with excess concentrated \(\text{H}_2\text{SO}_4\) at \(170\ ^\circ\text{C}\); Step 2: Heat with \(\text{H}_2\text{O}\) in the presence of \(\text{H}^+\)
- B.Step 1: Reflux with acidified \(\text{K}_2\text{Cr}_2\text{O}_7\text{(aq)}\); Step 2: React with \(\text{NaBH}_4\)
- C.Step 1: Reflux with concentrated \(\text{HCl}\text{(aq)}\) in the presence of anhydrous \(\text{ZnCl}_2\); Step 2: Heat with \(\text{NaOH}\text{(aq)}\)
- D.Step 1: React with \(\text{PBr}_3\); Step 2: Heat with \(\text{KOH(aq)}\)
Three metals, \(X\), \(Y\), and \(Z\), have the following properties: (1) Oxide of \(X\) can be reduced by heating with carbon, but oxide of \(Y\) cannot. (2) When a piece of metal \(X\) is placed in an aqueous solution of nitrate of \(Z\), a grey deposit is formed on the surface of \(X\). (3) Metal \(Y\) reacts with cold water to liberate hydrogen gas, while metal \(X\) does not. Which of the following arrangements shows the order of reactivity of these metals (from the most reactive to the least reactive)?
- A.\(Y > X > Z\)
- B.\(Y > Z > X\)
- C.\(X > Y > Z\)
- D.\(Z > Y > X\)
A reaction has a rate constant \(k_1 = 2.0 \times 10^{-3}\text{ s}^{-1}\) at \(300\text{ K}\), and \(k_2 = 8.0 \times 10^{-3}\text{ s}^{-1}\) at \(320\text{ K}\). What is the activation energy (\(E_a\)) of this reaction? (Given: Gas constant \(R = 8.31\text{ J mol}^{-1}\text{ K}^{-1}\))
- A.\(55.3\text{ kJ mol}^{-1}\)
- B.\(110.6\text{ kJ mol}^{-1}\)
- C.\(23.0\text{ kJ mol}^{-1}\)
- D.\(5.53\text{ kJ mol}^{-1}\)
Consider an alkaline hydrogen-oxygen fuel cell. Which of the following statements is/are correct? (1) The reaction at the anode is \(\text{O}_2\text{(g)} + 2\text{H}_2\text{O(l)} + 4e^- \rightarrow 4\text{OH}^-\text{(aq)}\). (2) Potassium hydroxide solution is commonly used as the electrolyte. (3) The overall cell reaction produces water as the only product.
- A.(1) only
- B.(2) only
- C.(1) and (3) only
- D.(2) and (3) only
A \(1.50\text{ g}\) sample of impure limestone (mainly containing \(\text{CaCO}_3\)) was reacted with \(50.0\text{ cm}^3\) of \(0.500\text{ M HCl(aq)}\). After the reaction was complete, the excess acid required \(15.0\text{ cm}^3\) of \(0.200\text{ M NaOH(aq)}\) for complete neutralization. What is the percentage by mass of \(\text{CaCO}_3\) in the sample? (Molar mass of \(\text{CaCO}_3 = 100.1\text{ g mol}^{-1}\))
- A.73.4%
- B.83.4%
- C.36.7%
- D.93.4%
Which of the following pairs of compounds cannot be distinguished by identifying characteristic functional group absorptions in infrared (IR) spectroscopy alone?
- A.Ethanol and ethanoic acid
- B.Propan-1-ol and propanal
- C.Ethanoic acid and ethyl ethanoate
- D.Methyl propanoate and ethyl ethanoate
Which of the following groups of species all have a trigonal planar shape?
- A.\(\text{BF}_3\), \(\text{CO}_3^{2-}\), \(\text{NO}_3^-\)
- B.\(\text{NH}_3\), \(\text{PCl}_3\), \(\text{H}_3\text{O}^+\)
- C.\(\text{CH}_4\), \(\text{SiF}_4\), \(\text{NH}_4^+\)
- D.\(\text{O}_3\), \(\text{SO}_2\), \(\text{NO}_2^-\)
Maleic anhydride (\(\text{C}_4\text{H}_2\text{O}_3\)) can be produced by the catalytic oxidation of butene as shown in the equation below: \(\text{C}_4\text{H}_8 + 3\text{O}_2 \rightarrow \text{C}_4\text{H}_2\text{O}_3 + 3\text{H}_2\text{O}\). What is the atom economy of this reaction for the production of maleic anhydride? (Relative atomic masses: \(\text{H} = 1.0\), \(\text{C} = 12.0\), \(\text{O} = 16.0\))
- A.64.5%
- B.44.1%
- C.84.5%
- D.35.5%
Consider the following thermochemical equations:
1) \( \text{C(graphite)} + \text{O}_2\text{(g)} \rightarrow \text{CO}_2\text{(g)} \quad \Delta H_1 = -393.5 \text{ kJ mol}^{-1} \)
2) \( \text{H}_2\text{(g)} + \frac{1}{2}\text{O}_2\text{(g)} \rightarrow \text{H}_2\text{O(l)} \quad \Delta H_2 = -285.8 \text{ kJ mol}^{-1} \)
3) \( 2\text{C(graphite)} + 3\text{H}_2\text{(g)} + \frac{1}{2}\text{O}_2\text{(g)} \rightarrow \text{C}_2\text{H}_5\text{OH(l)} \quad \Delta H_3 = -277.6 \text{ kJ mol}^{-1} \)
What is the standard enthalpy change of combustion of liquid ethanol (\( \text{C}_2\text{H}_5\text{OH(l)} \))?
- A.\( -1366.8 \text{ kJ mol}^{-1} \)
- B.\( -956.8 \text{ kJ mol}^{-1} \)
- C.\( -401.7 \text{ kJ mol}^{-1} \)
- D.\( -1921.8 \text{ kJ mol}^{-1} \)
Which of the following processes involves an oxidation in which the oxidation number of sulfur increases by exactly 4?
- A.Burning sulfur in excess oxygen to form sulfur dioxide.
- B.Reaction of hydrogen sulfide with sulfur dioxide to form sulfur.
- C.Reaction of sulfur dioxide with acidified potassium dichromate(VI) solution.
- D.Reaction of copper with concentrated sulfuric acid to produce sulfur dioxide.
What is the systematic IUPAC name of the compound below?
\( \text{CH}_3\text{CH(CH}_3\text{)C(CH}_3\text{)=CHCH}_3 \)
- A.2,3-dimethylpent-3-ene
- B.3,4-dimethylpent-2-ene
- C.2,3-dimethylpent-2-ene
- D.1,2,3-trimethylbut-2-ene
An organic compound \( X \) has the molecular formula \( \text{C}_4\text{H}_8\text{O} \). It does not react with acidified potassium dichromate(VI) solution upon warming, nor does it react with sodium metal. Which of the following is the correct structure of \( X \)?
- A.\( \text{CH}_3\text{CH}_2\text{CH}_2\text{CHO} \)
- B.\( \text{CH}_3\text{CH(OH)CH=CH}_2 \)
- C.\( \text{CH}_3\text{COCH}_2\text{CH}_3 \)
- D.\( \text{CH}_2\text{=CHCH}_2\text{CH}_2\text{OH} \)
The rate constant \( k \) of a certain reaction was measured at different temperatures. A plot of \( \ln k \) against \( \frac{1}{T} \) (where \( T \) is temperature in Kelvin) yielded a straight line with a slope of \( -1.20 \times 10^4 \text{ K} \). What is the activation energy (\( E_a \)) of this reaction?
(Given: Gas constant \( R = 8.31 \text{ J mol}^{-1}\text{ K}^{-1} \))
- A.\( 1.44 \text{ kJ mol}^{-1} \)
- B.\( 14.4 \text{ kJ mol}^{-1} \)
- C.\( 99.7 \text{ kJ mol}^{-1} \)
- D.\( 997 \text{ kJ mol}^{-1} \)
Maleic anhydride (\( \text{C}_4\text{H}_2\text{O}_3 \)) can be synthesized via two different routes:
Route 1: \( 2\text{C}_6\text{H}_6 + 9\text{O}_2 \rightarrow 2\text{C}_4\text{H}_2\text{O}_3 + 4\text{CO}_2 + 4\text{H}_2\text{O} \)
Route 2: \( \text{C}_4\text{H}_8 + 3\text{O}_2 \rightarrow \text{C}_4\text{H}_2\text{O}_3 + 3\text{H}_2\text{O} \)
Which route is greener according to the principle of atom economy?
(Relative atomic masses: \( \text{H} = 1.0 \), \( \text{C} = 12.0 \), \( \text{O} = 16.0 \))
- A.Route 1 is greener because its atom economy is 64.5%, compared to 44.1% for Route 2.
- B.Route 2 is greener because its atom economy is 64.5%, compared to 44.1% for Route 1.
- C.Route 1 is greener because its atom economy is 55.9%, compared to 35.5% for Route 2.
- D.Route 2 is greener because its atom economy is 82.1%, compared to 17.9% for Route 1.
A \( 25.00 \text{ cm}^3 \) sample of commercial bleach containing sodium hypochlorite (\( \text{NaOCl} \)) was diluted to \( 250.0 \text{ cm}^3 \). A \( 25.00 \text{ cm}^3 \) portion of this diluted solution was acidified and reacted with excess KI(aq). The liberated iodine required \( 22.40 \text{ cm}^3 \) of \( 0.100 \text{ mol dm}^{-3} \) \( \text{Na}_2\text{S}_2\text{O}_3\text{(aq)} \) for complete titration.
What is the concentration of \( \text{NaOCl} \) in the original commercial bleach?
(Equations:
\( \text{OCl}^- + 2\text{I}^- + 2\text{H}^+ \rightarrow \text{Cl}^- + \text{I}_2 + \text{H}_2\text{O} \)
\( \text{I}_2 + 2\text{S}_2\text{O}_3^{2-} \rightarrow 2\text{I}^- + \text{S}_4\text{O}_6^{2-} \))
- A.\( 0.0448 \text{ mol dm}^{-3} \)
- B.\( 0.224 \text{ mol dm}^{-3} \)
- C.\( 0.448 \text{ mol dm}^{-3} \)
- D.\( 0.896 \text{ mol dm}^{-3} \)
An organic compound \( Y \) has a molecular formula \( \text{C}_3\text{H}_6\text{O}_2 \). Its infrared (IR) spectrum shows a strong broad absorption band around \( 3000 \text{ cm}^{-1} \) and a strong sharp absorption band around \( 1715 \text{ cm}^{-1} \). Which of the following statements about the mass spectrum of \( Y \) is correct?
- A.The molecular ion peak occurs at \( m/z = 60 \).
- B.It shows a prominent peak at \( m/z = 45 \), corresponding to the species \( [\text{COOH}]^+ \).
- C.It shows a prominent peak at \( m/z = 43 \), corresponding to the species \( [\text{C}_3\text{H}_7]^+ \).
- D.There is a prominent peak at \( m/z = 15 \) due to the loss of a water molecule.
Which of the following mixtures, when heated strongly, will undergo a displacement reaction?
- A.\( \text{MgO} \) and \( \text{Fe} \)
- B.\( \text{Al}_2\text{O}_3 \) and \( \text{Cu} \)
- C.\( \text{Fe}_2\text{O}_3 \) and \( \text{Al} \)
- D.\( \text{ZnO} \) and \( \text{Pb} \)
Which of the following molecules / ions has the same shape as the hydronium ion (\( \text{H}_3\text{O}^+ \))?
- A.\( \text{BF}_3 \)
- B.\( \text{PCl}_3 \)
- C.\( \text{CO}_3^{2-} \)
- D.\( \text{ClF}_3 \)
Consider the following standard enthalpy changes of combustion (\(\Delta H_c^\theta\)) at \(298\text{ K}\): \(\text{C(graphite)} = -393.5\text{ kJ mol}^{-1}\), \(\text{H}_2\text{(g)} = -285.8\text{ kJ mol}^{-1}\), \(\text{C}_3\text{H}_8\text{(g)} = -2220.0\text{ kJ mol}^{-1}\). What is the standard enthalpy change of formation of propane (\(\text{C}_3\text{H}_8\text{(g)}\)) at \(298\text{ K}\)?
- A.-103.7 kJ mol^{-1}
- B.-1540.7 kJ mol^{-1}
- C.+103.7 kJ mol^{-1}
- D.+1540.7 kJ mol^{-1}
A chemical cell is set up by connecting a zinc-zinc(II) ion half-cell and a copper-copper(II) ion half-cell using a salt bridge. If the zinc electrode and its solution are replaced by a nickel electrode and a nickel(II) ion solution under the same conditions, which of the following statements is/are correct? (Given standard reduction potentials: \(E^\theta(\text{Zn}^{2+}/\text{Zn}) = -0.76\text{ V}\); \(E^\theta(\text{Ni}^{2+}/\text{Ni}) = -0.25\text{ V}\); \(E^\theta(\text{Cu}^{2+}/\text{Cu}) = +0.34\text{ V}\)) (1) The cell voltage decreases. (2) Electrons still flow from the other electrode to the copper electrode through the external circuit. (3) The mass of the nickel electrode increases.
- A.(1) only
- B.(1) and (2) only
- C.(2) and (3) only
- D.(1), (2) and (3)
What is the IUPAC name of the compound with the following structure? \(\text{ClCH}_2\text{CH}=\text{CHCH(CH}_3)_2\)
- A.5-chloro-2-methylpent-3-ene
- B.1-chloro-4-methylpent-2-ene
- C.1-chloro-4,4-dimethylbut-2-ene
- D.4-isopropyl-1-chlorobut-2-ene
Consider the following reaction route: Compound X \(\xrightarrow{\text{acidified }\text{K}_2\text{Cr}_2\text{O}_7\text{(aq), heat under reflux}}\). Compound Y \(\xrightarrow{\text{CH}_3\text{CH}_2\text{OH, conc. }\text{H}_2\text{SO}_4\text{, heat}}\). Compound Z. If Compound Z has the molecular formula \(\text{C}_5\text{H}_{10}\text{O}_2\), what is the IUPAC name of Compound X?
- A.propan-1-ol
- B.propan-2-ol
- C.propanoic acid
- D.ethyl propanoate
A \(2.50\text{ g}\) sample of an eggshell was treated with \(50.0\text{ cm}^3\) of \(0.500\text{ M }\text{HCl(aq)}\). After the reaction was complete, the remaining solution required \(16.8\text{ cm}^3\) of \(0.250\text{ M }\text{NaOH(aq)}\) for complete neutralization. What is the percentage by mass of calcium carbonate (\(\text{CaCO}_3\)) in the eggshell? (Relative atomic masses: \(C = 12.0\), \(O = 16.0\), \(Ca = 40.1\))
- A.20.8%
- B.41.6%
- C.83.3%
- D.91.6%
For a particular chemical reaction, a plot of \(\ln k\) against \(\frac{1}{T}\) gives a straight line with a slope of \(-1.20 \times 10^4\text{ K}\), where \(k\) is the rate constant and \(T\) is the temperature in Kelvin. What is the activation energy of this reaction? (Given: gas constant \(R = 8.314\text{ J mol}^{-1}\text{ K}^{-1}\))
- A.99.8 kJ mol^{-1}
- B.1.44 kJ mol^{-1}
- C.12.0 kJ mol^{-1}
- D.99.8 J mol^{-1}
Acetanilide (\(\text{C}_8\text{H}_9\text{NO}\)) is prepared by reacting aniline (\(\text{C}_6\text{H}_5\text{NH}_2\)) with acetic anhydride (\((\text{CH}_3\text{CO})_2\text{O}\)) according to the following equation: \(\text{C}_6\text{H}_5\text{NH}_2 + (\text{CH}_3\text{CO})_2\text{O} \rightarrow \text{C}_6\text{H}_5\text{NHCOCH}_3 + \text{CH}_3\text{COOH}\). What is the atom economy of this reaction for the synthesis of acetanilide? (Relative atomic masses: \(H = 1.0\), \(C = 12.0\), \(N = 14.0\), \(O = 16.0\))
- A.30.8%
- B.44.4%
- C.69.2%
- D.100%
An organic compound X shows a strong and broad absorption band in the range \(3230 - 3670\text{ cm}^{-1}\) in its infrared spectrum. Compound X does not cause any color change when heated with acidified \(\text{K}_2\text{Cr}_2\text{O}_7\text{(aq)}\). Which of the following is most likely Compound X?
- A.propan-1-ol
- B.propan-2-ol
- C.2-methylpropan-2-ol
- D.propanoic acid
Consider the following experimental observations on three metals, P, Q, and R: (1) Metal P reacts vigorously with cold water to produce a gas. (2) The oxide of Q can be reduced by heating with carbon, but the oxide of P cannot. (3) When metal Q is added to an aqueous solution containing ions of R, a deposit of metal R is formed on the surface of Q. Which of the following is the correct order of reactivity of the metals in decreasing order?
- A.P > Q > R
- B.P > R > Q
- C.Q > P > R
- D.R > Q > P
Which of the following pairs of chemical species has the same molecular / ionic shape?
- A.BF3 and NH3
- B.CH4 and NH4+
- C.H2O and CO2
- D.PCl3 and BF3
Consider the following standard enthalpy changes:
\( \text{C(graphite)} + \text{O}_2\text{(g)} \rightarrow \text{CO}_2\text{(g)} \quad \Delta H^\theta = -393.5 \text{ kJ mol}^{-1} \)
\( 2\text{H}_2\text{(g)} + \text{O}_2\text{(g)} \rightarrow 2\text{H}_2\text{O(l)} \quad \Delta H^\theta = -571.6 \text{ kJ mol}^{-1} \)
\( 2\text{C}_2\text{H}_2\text{(g)} + 5\text{O}_2\text{(g)} \rightarrow 4\text{CO}_2\text{(g)} + 2\text{H}_2\text{O(l)} \quad \Delta H^\theta = -2598.8 \text{ kJ mol}^{-1} \)
What is the standard enthalpy change of formation of ethyne (\(\text{C}_2\text{H}_2\text{(g)}\))?
- A.-226.6 kJ mol^-1
- B.+113.3 kJ mol^-1
- C.+226.6 kJ mol^-1
- D.+453.2 kJ mol^-1
In which of the following species does vanadium have an oxidation number of +4?
(1) \(\text{VO}^{2+}\)
(2) \(\text{VO}_2\)
(3) \(\text{VCl}_4\)
- A.(1) and (2) only
- B.(1) and (3) only
- C.(2) and (3) only
- D.(1), (2) and (3)
An organic compound \(X\) has the molecular formula \(\text{C}_4\text{H}_8\text{O}_2\). It does not react with sodium metal to give hydrogen gas, nor does it react with sodium hydrogencarbonate solution. To which of the following homologous series could \(X\) belong?
- A.Carboxylic acids
- B.Esters
- C.Diols
- D.Alcohols
A mixture of gas \(X\) and gas \(Y\) reacts to form gas \(Z\). Which of the following changes would increase BOTH the rate of the reaction and the fraction of reactant molecules having energy equal to or greater than the activation energy?
(1) Increasing the temperature of the reaction mixture
(2) Adding a suitable catalyst
(3) Increasing the pressure of the system by reducing the volume of the container
- A.(1) only
- B.(1) and (2) only
- C.(2) and (3) only
- D.(1), (2) and (3)
How many acyclic structural isomers (excluding stereoisomers) exist for the compound with the molecular formula \(\text{C}_3\text{H}_5\text{Cl}_3\)?
- A.4
- B.5
- C.6
- D.7
In a standardisation experiment, a student transfers \(25.00 \text{ cm}^3\) of a standard sodium carbonate solution into a conical flask using a pipette, and titrates it against a hydrochloric acid solution of unknown concentration delivered from a burette.
Which of the following experimental errors would result in an OVERESTIMATION of the calculated concentration of the hydrochloric acid solution?
- A.Rinsing the pipette with distilled water only before transferring the sodium carbonate solution.
- B.Rinsing the conical flask with the sodium carbonate solution before the titration.
- C.Rinsing the burette with distilled water only before filling it with the hydrochloric acid solution.
- D.Leaving an air bubble in the tip of the burette which is dislodged during the titration.