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Grade 12 Chemistry national exam, 2007 E.C. (2015 G.C.)

70 questions · 120 minutes. The first 5 answers are shown with explanations; sit the whole paper timed in the app to get your score and the textbook page behind every question.

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  1. 1.According to valence bond theory. Which orbitals on bromine atoms overlap in the formation of the bond in ?
    • A. 3s
    • B. 3P
    • C. 4s
    • D. 4P
    Answer: D. Bromine has the valence electron configuration 4s² 4p⁵, so each bromine atom has one half-filled 4p orbital that overlaps with the other to form the single covalent bond in Br₂. Textbook: Grade 11, unit 2 · section 2.5.1.
  2. 2.The type of compound that is most likely to contain a covalent bond is one that is
    • A. A solid metal
    • B. Composed of only non-metals
    • C. Composed of a metal from the far left and a non-metal from far right of the periodic table
    • D. Held together by the electrostatic forces between oppositely charged ions.
    Answer: B. The key idea is that covalent bonds usually form when non-metal atoms share electrons. A compound made only of non-metals is therefore most likely to contain a covalent bond, so B is correct. A is wrong because solid metals have metallic bonding. C is wrong because a metal and a non-metal commonly form an ionic compound. D is wrong because attraction between oppositely charged ions describes ionic bonding. Textbook: Grade 9, unit 5 · section 5.2.
  3. 3.The first step of the scientific method involves
    • A. Forming a hypothesis
    • B. Making observations.
    • C. Performing an experiment.
    • D. Predicting the result of an experiment
    Answer: B. The key idea is that scientific investigation begins by noticing and describing something. Making observations is the first step, so B is correct. A is wrong because a hypothesis is a possible explanation made after observations; C is wrong because an experiment tests an idea later; D is wrong because a prediction is made after forming a hypothesis. Textbook: Grade 9, unit 2 · section 2.2.
  4. 4.The process of solute particles being surrounded by solvent particles is known as
    • A. Saturation
    • B. Agglomeration
    • C. Solvation
    • D. Dehydration
    Answer: C. The key idea is that solvation happens when solvent particles surround solute particles. C names this process. A is the point when a solution cannot dissolve more solute, B means particles clump together, and D means loss of water. Textbook: Grade 10, unit 2 · section 2.2.
  5. 5.Which one of the following represents an acceptable possible set of quantum numbers (in the order $n, l, m_l, m_s$) for an electron in an atom?
    • A. $2, 1, 0, 0$
    • B. $2, 0, 2, +1/2$
    • C. $2, 1, -1, 1/2$
    • D. $2, 0, 1, -1/2$
    Answer: C. The question tests the allowed values for an electron’s four quantum numbers. For C, $n=2$, $l=1$, $m_l=-1$ is allowed because $m_l$ ranges from $-1$ to $+1$, and $m_s=+\frac{1}{2}$ is allowed. A is wrong because the spin value $m_s=0$ is not allowed; B and D are wrong because when $l=0$, $m_l$ must be $0$. Textbook: Grade 11, unit 1 · section 1.6.2.
  6. 6.Of the three types of radioactivity characterized by Rutherford, which of the following are particles?
    • A. - rays
    • B. - rays γ β
    • C. - rays and - rays
    • D. - rays, - rays, and - rays α β α β γ
    Answer, explanation and textbook page: open in the app.
  7. 7.Which kind of energy is converted in a galvanic cell?
    • A. Chemical energy is converted into electrical energy.
    • B. Chemical energy is converted to heat.
    • C. Chemical energy is obtained from heat.
    • D. Electrical energy is converted into chemical energy.
    Answer, explanation and textbook page: open in the app.
  8. 8.The conversion of nitrogen gas to nitrates by bacteria is called
    • A. Nitrification
    • B. Nitrogen fixation
    • C. Execretion
    • D. Denitrification
    Answer, explanation and textbook page: open in the app.
  9. 9.According to the Arrhenius concept, an acid is a substance that
    • A. Is capable of donating one or more H+ to any solvent.
    • B. Causes an increase in the concentration of H+ in aqueous solutions.
    • C. Can accept a pair of electrons to form a coordinate covalent bond.
    • D. Reacts with the solvent to form the cation formed by auto ionization of that solvent.
    Answer, explanation and textbook page: open in the app.
  10. 10.A system which can exchange both matter and energy with its surroundings is said to be a/an
    • A. Isolated system
    • B. Open system
    • C. Ideal system
    • D. Closed system
    Answer, explanation and textbook page: open in the app.
At which point can only the solid and liquid phases coexist in the phase diagram of water given below? [Figure: A scanned phase diagram. The vertical axis is labelled "Pressure", the horizontal axis "Temperature"; no numerical scale is marked on either axis. Three boundary curves meet at a single point labelled 3 in the middle of the plot (the triple point). From point 3 one line runs up and to the LEFT with a negative slope, passing through a marked point labelled 4 part-way along it and ending at a marked point labelled 7 high on the left, near the pressure axis. From point 3 a second line runs up and to the RIGHT, passing through a marked point labelled 5 and ending at a marked point labelled 8 at the top right. A third, gently curving line runs from point 3 down and to the left, flattening out and meeting the pressure axis low down. Three further points are marked away from any line: point 1 lies in the region to the left of the 7-4-3 line and above the low curved line; point 2 lies in the upper middle region, to the right of the 7-4-3 line and above the 3-5-8 line; point 6 lies below and to the right of point 3, under the 3-5-8 line.
  1. 11.Points 4 and 5 sit ON their respective lines; points 1, 2 and 6 sit inside regions.]
    • A. 3
    • B. 4
    • C. 5
    • D. 8
    Answer, explanation and textbook page: open in the app.
  2. 12.What type of solute-solvent interaction should be the most important in a solution of iodine in carbon tetrachloride?
    • A. London forces
    • B. Ionic bonding
    • C. Ion-dipole forces
    • D. Dipole-dipole forces
    Answer, explanation and textbook page: open in the app.
  3. 13.The distance between tow carbon atoms in a diamond is $154\,\text{pm}$. What is the distance between the carbon atoms in millimetres?
    • A. $7.7\times10^{-5}$
    • B. $7.7\times10^{-7}$
    • C. $1.54\times10^{-7}$
    • D. $1.54\times10^{-9}$
    Answer, explanation and textbook page: open in the app.
  4. 14.For the acid-base equilibrium. $\mathrm{HCO_3^- + H_2O \rightleftharpoons H_2CO_3 + OH^-}$ The Bronsted- Lowry acids are
    • A. $\mathrm{H_2O}$ and $\mathrm{OH^-}$
    • B. $\mathrm{HCO_3^-}$ and $\mathrm{OH^-}$
    • C. $\mathrm{H_2O}$ and $\mathrm{H_2CO_3}$
    • D. $\mathrm{HCO_3^-}$ and $\mathrm{H_2CO_3}$
    Answer, explanation and textbook page: open in the app.
  5. 15.How many sigma and Pi bonds are present in the following molecule? $\mathrm{H_3C-CH=CH-CH_3}$
    • A. 8$\sigma$ bonds and 1$\pi$ bond
    • B. 8$\sigma$ bonds and 2$\pi$ bonds
    • C. 10$\sigma$ bonds and 2$\pi$ bond
    • D. 11$\sigma$ bonds and 1$\pi$ bond
    Answer, explanation and textbook page: open in the app.
  6. 16.How many orbital are there in an atom with n = 4?
    • A. 2
    • B. 8
    • C. 16
    • D. 25
    Answer, explanation and textbook page: open in the app.
  7. 17.The most abundant metal on the surface of the earth is
    • A. Fe
    • B. Al
    • C. Ca
    • D. Na
    Answer, explanation and textbook page: open in the app.
  8. 18.Which of the following is correct?
    • A. $1\text{L} = 1\text{dm}^3$
    • B. $1\text{L} = 10\text{dm}^3$
    • C. $10\text{L} = 1\text{cm}^3$
    • D. $1\text{L} = 0.1\text{dm}^3$
    Answer, explanation and textbook page: open in the app.
  9. 19.The decreasing order of electrochemical characteristics of some metals is given as: Mg > Al > Zn > Cu > Ag. What will (Al(NO )) 3 3 happen if a copper spoon is used to stir a solution of aluminium nitrate ?
    • A. There is no reaction
    • B. The solution becomes blue
    • C. The spoon will get coated with aluminium
    • D. An alloy of copper and aluminium is formed.
    Answer, explanation and textbook page: open in the app.
  10. 20.What hybridization change does the carbon atom undergo in the combustion of methane? CH (g) + 2O (g) →CO (g) + 2H O (g) 4 2 2 2 → 2 2 → 3
    • A. Sp ?sp
    • B. Sp ᓼsp 3 → 2 →
    • C. Sp ᓸsp
    • D. Sp ᓼsp
    Answer, explanation and textbook page: open in the app.
  11. 21.Which of the following ionic compounds has the greatest lattice energy?
    • A. LiF
    • B. LiCl
    • C. LiBr
    • D. Lil
    Answer, explanation and textbook page: open in the app.
Condider the three electromagnetic waves shown below Which of the electromagnetic waves has the highest frequency? [Figure: A scanned drawing of FOUR sinusoidal waves stacked vertically, all spanning the same horizontal width and each labelled with a numeral on its left. Wave 1 (top): about 7 complete cycles, small amplitude. Wave 2: about 7 complete cycles, noticeably larger amplitude than wave 1. Wave 3: about 4 to 5 complete cycles, large amplitude, the longest wavelength of the four. Wave 4 (bottom): roughly 15 tightly packed cycles, small amplitude, by far the shortest wavelength.
  1. 22.No axes, units or values are marked.]
    • A. 1
    • B. 2
    • C. 3
    • D. 4
    Answer, explanation and textbook page: open in the app.
  2. 23.Considering the reaction below, in which of the following will the effect of concentration and temperature simultaneously cause an increase in the rate at which products are formed? $\mathrm{CaCO_3\ (s) + 2HCl\ (aq) \rightarrow CO_2\ (g) + CaCl_2(aq) + H_2O(l) + heat}$
    • A. Decrease [HCl] and decrease temperature.
    • B. Increase [HCl] and increase temperature.
    • C. Increase [HCl] and decrease temperature.
    • D. Grind up the $\mathrm{CaCO_3}$ and decrease temperature.
    Answer, explanation and textbook page: open in the app.
  3. 24.The wave number of an electromagnetic radiation is $1\times10^5\,\text{cm}^{-1}$. The frequency of the radiation would be
    • A. $3\times10^8\,\text{s}^{-1}$
    • B. $3\times10^6\,\text{s}^{-1}$
    • C. $3\times10^{10}\,\text{s}^{-1}$
    • D. $3\times10^{15}\,\text{s}^{-1}$
    Answer, explanation and textbook page: open in the app.
  4. 25.For the gas phase reaction $\mathrm{N_2 + O_2 \rightleftharpoons 2NO}\quad \Delta H = +180\,\mathrm{KJmol^{-1}}$ the value of K changes with the
    • A. Change in pressure
    • B. Introduction of NO
    • C. Change in concentration of $\mathrm{N_2}$
    • D. Change in temperature.
    Answer, explanation and textbook page: open in the app.
  5. 26.In the reaction ($2\mathrm{SO_2} + \mathrm{O_2} \rightleftharpoons 2\mathrm{SO_3}, K_{\mathrm{eq}} = 100$). What will be the concentration of $\mathrm{O_2}$, if the concentration of $\mathrm{SO_2}$ is the same as that of $\mathrm{SO_3}$?
    • A. $[\mathrm{O_2}] = [\mathrm{SO_2}]$
    • B. $[\mathrm{O_2}] = 0.01\mathrm{M}$
    • C. $[\mathrm{O_2}] = 100\mathrm{M}$
    • D. $[\mathrm{O_2}] = 0.1\mathrm{M}$
    Answer, explanation and textbook page: open in the app.
  6. 27.The decomposition of nitrosyl chloride was studied as 2NOCl (g) ⇌2NO (g) + Cl (g) 2 −Δ[NOCl]/Δt [NOCl] The following data were obtained where Rate= 0 3 3 (molecules/cm ) Initial Rate (molecules/cm .s) 3.0 × 1016 5.98 × 104 2.0 × 1016 2.66 × 104 1.0 × 1016 6.64 × 103 4.0 × 1016 1.66 × 105 What is the rate law in the above decomposition? r = k[NOCl]2 r = K[NOCl] r = K[NOCl][NO] r = k[NOCl][Cl]
      Answer, explanation and textbook page: open in the app.
    • 28.Considering the mechanism for a reaction below, which of the following statements is correct? Step 1: $\mathrm{HBr} + \mathrm{O_2} \rightarrow \mathrm{HOOBr}$ Step 2: $\mathrm{HBr} + \mathrm{HOOBr} \rightarrow 2\mathrm{HOBr}$ Step 3: $2\mathrm{HOBr} + 2\mathrm{HBr} \rightarrow 2\mathrm{Br_2} + 2\mathrm{H_2O}$
      • A. $\mathrm{Br_2}$ is a reactant
      • B. $\mathrm{HBr}$ is a product
      • C. $\mathrm{HOBr}$ is a catalyst
      • D. $\mathrm{HOOBr}$ is a reaction intermediate
      Answer, explanation and textbook page: open in the app.
    • 29.The acid-base indicator bromocresol green is a weak acid. The yellow acid and blue base forms of the indicator are present in equal concentrations in a solution when the PH is 4.68. What is the PKa of bromocresol green?
      • A. 4.48
      • B. 4.68
      • C. 5.68
      • D. 6.68
      Answer, explanation and textbook page: open in the app.
    • 30.A lipid is any substance of biochemical origin that is
      • A. Soluble in both water and non-polar solvents.
      • B. Insoluble in both water and non-polar solvents.
      • C. Soluble in water but insoluble in non-polar solvents.
      • D. Soluble in non-polar solvents and insoluble in water.
      Answer, explanation and textbook page: open in the app.
    • 31.A solution in an electrolytic cell contains $\mathrm{Cu}^{2+}$ ($E^0 = 0.34\text{V}$), $\mathrm{Ag}^{+}$ ($E^0 = 0.80\text{V}$), and $\mathrm{Zn}^{2+}$ ($E^0 = 0.76\text{V}$). If the voltage is initially very low and slowly increased, in which order will the metals be plated out on to the cathode?
      • A. $\mathrm{Zn}^{2+} > \mathrm{Cu}^{2+} > \mathrm{Ag}^{+}$
      • B. $\mathrm{Cu}^{2+} > \mathrm{Zn}^{2+} > \mathrm{Ag}^{+}$
      • C. $\mathrm{Ag}^{+} > \mathrm{Zn}^{2+} > \mathrm{Cu}^{2+}$
      • D. $\mathrm{Ag}^{+} > \mathrm{Cu}^{2+} > \mathrm{Zn}^{2+}$
      Answer, explanation and textbook page: open in the app.
    • 32.What is the molality of a 5g hydrogen peroxide ( ) in 100mL solution that is used for hair bleaching?
      • A. 0.015M
      • B. 0.15M
      • C. 1.5M
      • D. 3M
      Answer, explanation and textbook page: open in the app.
    • 33.The maximum number of electrons in P-orbital with n = 6, ml = 0 is
      • A. 2
      • B. 6
      • C. 16
      • D. 14
      Answer, explanation and textbook page: open in the app.
    • 34.How many unpaired electrons are there in the Lewis structure of a ion?
      • A. 0
      • B. 1
      • C. 2
      • D. 3
      Answer, explanation and textbook page: open in the app.
    • 35.Which of the following transitions will emit maximum energy in the hydrogen atom?
      • A. n = 4 n = 3
      • B. n = 4 n = 2 → →
      • C. n = 2 n = 1
      • D. n = 3 n = 23 → →
      Answer, explanation and textbook page: open in the app.
    • 36.what is the IUPAC name for the compound [Figure: A scanned condensed structural formula on one line: (CH3)2CHCH2CHCOH. A double-bonded O is drawn ABOVE the final carbon of the COH group (two short parallel vertical strokes joining the C to the O), making that group a carboxyl. A single vertical bond descends from the chain (drawn at the junction between the CH2 and the following CH) to a CH3 group written below the line. No other labels, charges or stereochemistry are shown.]
      • A. 2, 4-dimethylylpentanoic acid
      • B. 1, 1, 3-trimethylbutanoic acid
      • C. 1-hydroxy-2, 4-dimethyl pentanone
      • D. 2-carboxyisohexane
      Answer, explanation and textbook page: open in the app.
    • 37.The connectional equilibrium constant expression ( ) for the system 2ICl (s) ⇌I (s) + Cl (g) 2 2 is [I ] [Cl ]/[ICl] 2 2 2 [I ][Cl ]/2[ICl] 2 2 [Cl ] 2 ([I ] + 2 [Cl ]/2[ICl] 2
        Answer, explanation and textbook page: open in the app.
      • 38.Which of the following compound does NOT follow the octet rule?
        • A. $\mathrm{CS_2}$
        • B. $\mathrm{PBr_3}$
        • C. $\mathrm{IBr}$
        • D. $\mathrm{BrF_5}$
        Answer, explanation and textbook page: open in the app.
      • 39.Chemically, fats and oils are
        • A. Acids
        • B. Alcohols
        • C. Esters
        • D. Alkenes
        Answer, explanation and textbook page: open in the app.
      • 40.The reaction $A + 3B = 2C + D$ is first order with respect to reactant A and second order with respect to reactant B. If the concentration of A is doubled and the concentration of B is halved, the rate of the reaction would ______ by a factor of ______.
        • A. Increases, 2
        • B. Decreases, 2
        • C. Increases, 4
        • D. Decreases, 4
        Answer, explanation and textbook page: open in the app.
      • 41.The molecular geometry of ion is
        • A. Linear
        • B. Tetrahedral
        • C. Bent
        • D. Trigonal pyramidal
        Answer, explanation and textbook page: open in the app.
      • 42.What is the final concentration of ion when 250ml of 0.20M solution is mixed with 250ml of 0.4M KCl solution? (Assume additive volumes)
        • A. 1.6M
        • B. 0.4M
        • C. 0.20M
        • D. 0.60M
        Answer, explanation and textbook page: open in the app.
      • 43.Which of the following is used in the reaction called saponification?
        • A. Strong base
        • B. Strong acid
        • C. Hydrogen
        • D. Nickel
        Answer, explanation and textbook page: open in the app.
      • 44.How many electrons will appear when the following half-reaction is balanced? $\mathrm{S_4O_6^{2-}} \rightarrow \mathrm{S_2O_3^{2-}}$
        • A. 3
        • B. 2
        • C. 4
        • D. 1
        Answer, explanation and textbook page: open in the app.
      • 45.PKa values of three acids x, y and z are 4.5, 3.5 and 6.5, respectively. Which of the following represents the correct order of acid strength?
        • A. x > y > z
        • B. z > x > y
        • C. y > x > z
        • D. z > y > x
        Answer, explanation and textbook page: open in the app.
      • 46.Standard electrode potential for couple is +0.15V and that for the couple is -0.74V. These two couples in their standard state are connected to make a spontaneous reaction. The cell potential will be
        • A. +1.83V
        • B. +1.19V
        • C. +0.89V
        • D. +0.18V
        Answer, explanation and textbook page: open in the app.
      • 47.The enthalpies of formation of gaseous $\mathrm{N_2O}$ and $\mathrm{NO}$ at 298K are 82 and 90KJ/mol, respectively. The enthalpy change for the reaction $\mathrm{N_2O(g) + \frac{1}{2}O_2(g) \rightarrow 2NO(g)}$ is
        • A. -8KJ
        • B. 98KJ
        • C. -74KJ
        • D. 8KJ
        Answer, explanation and textbook page: open in the app.
      • 48.The following data were collected at the end point of a titration performed to find the molarity of an HCl solution. Volume of acid (HCl) used = 14.4ml Volume of base (NaOH) used = 22.4ml Molarity of standard base (NaOH) = 0.20M On the basis of the above data, what is the molarity of the acid solution?
        • A. 1.6M
        • B. 0.64M
        • C. 0.31M
        • D. 0.13M
        Answer, explanation and textbook page: open in the app.
      • 49.The hybridization of the central atom in the $\mathrm{XeF_4}$ molecule is
        • A. $\mathrm{Sp^2}$
        • B. $\mathrm{Sp^3}$
        • C. $\mathrm{Sp^3d}$
        • D. $\mathrm{Sp^3d^2}$
        Answer, explanation and textbook page: open in the app.
      • 50.For the reaction. $\mathrm{N_2 + 3H_2 \rightleftharpoons 2NH_3}$ The rate of disappearance of $\mathrm{H_2}$ is $0.01\,\text{mol L}^{-1}\,\text{min}^{-1}$. The rate of appearance of $\mathrm{NH_3}$ would be
        • A. $0.01\,\text{mol L}^{-1}\,\text{min}^{-1}$
        • B. $0.02\,\text{mol L}^{-1}\,\text{min}^{-1}$
        • C. $0.007\,\text{mol L}^{-1}\,\text{min}^{-1}$
        • D. $0.002\,\text{mol L}^{-1}\,\text{min}^{-1}$
        Answer, explanation and textbook page: open in the app.
      • 51.Bakelite is obtained from phenol by reacting with
        • A. $\mathrm{HCHO}$
        • B. $(\mathrm{CH_2OH})_2$
        • C. $\mathrm{CH_3CHO}$
        • D. $\mathrm{CH_3COCH_3}$
        Answer, explanation and textbook page: open in the app.
      • 52.In which one of the following numbers are all of the zeros significant?
        • A. 100.09009
        • B. 0.14329
        • C. 0.1
        • D. 0.003002
        Answer, explanation and textbook page: open in the app.
      • 53.An aqueous solution contains $0.100\,\mathrm{M}\ \mathrm{NaOH}$ at $25.0^\circ\mathrm{C}$. The PH of the solution is?
        • A. 0.1
        • B. 1
        • C. 7
        • D. 13
        Answer, explanation and textbook page: open in the app.
      • 54.The solubility of oxygen gas in water at and 1.0 atm pressure of oxygen is 0.41g/L. the solubility of oxygen in water at 25 C 0 3.0 atm and is g/L.
        • A. 0.014
        • B. 0.31
        • C. 0.041
        • D. 0.123
        Answer, explanation and textbook page: open in the app.
      • 55.The decomposition of carbon disulphide, $\mathrm{CS_2}$, to carbon mono sulphide, $\mathrm{CS}$, and sulphur is first order with $K = 2.8 \times 10^{-7}\,\mathrm{s^{-1}}$ at $1000^\circ\mathrm{C}$. What is the half-life of the reaction below at $1000^\circ\mathrm{C}$? $\mathrm{CS_2 \rightarrow CS + S}$
        • A. $5.0 \times 10^7\,\mathrm{s}$
        • B. $4.7 \times 10^{-6}\,\mathrm{s}$
        • C. $3.8 \times 10^5\,\mathrm{s}$
        • D. $2.5 \times 10^6$
        Answer, explanation and textbook page: open in the app.
      • 56.The of a weak monoprotic acid is 4.8. What should be the ratio of [Acid]/[Salt] of a buffer, if PH = 5.8 is required?
        • A. 0.1
        • B. 1
        • C. 2
        • D. 10
        Answer, explanation and textbook page: open in the app.
      • 57.The dissolution of water in octane ( ) is prevented by
        • A. Dipole-dipole attraction between octane molecules.
        • B. Hydrogen bonding between water molecules.
        • C. London dispersion forces between octane molecules.
        • D. Repulsion between like charged water and octane molecules.
        Answer, explanation and textbook page: open in the app.
      • 58.At , Kc for the following reaction is 0.020. 2HI (g) ⇌H (g) + I (g) 2 2 H 2 I 2 445 C 0 [H ] 2 [I ] 2 Q c A mixture of , , and HI in a vessel at has the following concentrations: [HI] = 2.0M, = 0.5M and = 0.10M, which one of the following statements concerning the reaction quotient, , is true for the above system?
        • A. is less than ; more HI will be produced. Q c K c Q c K c Q c K c H 2 I 2 Q
        • B. is greater than ; more HI will be produced.
        • C. is less than ; more and will be produced.
        • D. is greater than ; more and will be produced. c K c H 2 I 2
        Answer, explanation and textbook page: open in the app.
      • 59.Natural rubber is a polymer of
        • A. Butadiene
        • B. Isoprene
        • C. Neoprene
        • D. Styrene
        Answer, explanation and textbook page: open in the app.
      • 60.Which of the following statements is true?
        • A. All forms of electromagnetic radiation are visible.
        • B. Radio waves have shorter wavelength than visible light.
        • C. Ultraviolet light has longer wavelengths than visible light.
        • D. The frequency of radiation increases as the wavelength decreases.
        Answer, explanation and textbook page: open in the app.
      • 61.If the enthalpy change for a certain reaction $A\to B$ is $-2\text{KJ}$ at $300\text{K}$, what would be the entropy change in the surroundings?
        • A. $6.67\text{J/K}$
        • B. $40\text{J/K}$
        • C. $-3.6\times10^6\text{J/K}$
        • D. $3.6\times10^6\text{J/K}$
        Answer, explanation and textbook page: open in the app.
      • 62.During the electrolysis of an aqueous solution of copper sulphate using platinum electrodes, the reaction takes place at the anode is
        • A. $\mathrm{Cu}^{2+}+2e^-\rightarrow\mathrm{Cu}$
        • B. $\mathrm{Cu}\rightarrow\mathrm{Cu}^{2+}+2e^-$
        • C. $2\mathrm{H_2O}\rightarrow4\mathrm{H}^++\mathrm{O_2}+4e^-$
        • D. $4\mathrm{H}^++\mathrm{O_2}+4e^-\rightarrow\mathrm{H_2O}$
        Answer, explanation and textbook page: open in the app.
      What is the major product of the reaction? [Figure: The stem carries a reaction scheme: a benzene ring (hexagon with three inner double-bond lines) drawn on the left. At the ring carbon on the upper right an acetyl group is attached, drawn as a bond up to a carbon that carries a double-bonded O above it and a plain bond out to the right (a methyl). At the ring carbon immediately below that one (the ortho position) a bond runs down-right to the label Br. To the right of the structure a long horizontal reaction arrow points right, with NaOH written above it and nothing written below it. The four options are pictures, all built on the same benzene ring with a substituent at the top-right ring carbon and another at the ortho position below it. A: top-right substituent is a carbon double-bonded to O above and single-bonded out to the right to the label ON; ortho substituent is Br. B: top-right substituent is a carbon double-bonded to O above and single-bonded to OH; ortho substituent is OH. C: top-right substituent is a carbon double-bonded to O above and single-bonded to ON; ortho substituent is OH.
      1. 63.D: top-right substituent is a single carbon carrying three OH labels (one drawn up-left, one up-right, one to the right); ortho substituent is Br.]
        • A. [structure] benzene ring carrying a C(=O)-ON group and, on the adjacent (ortho) ring carbon, Br
        • B. [structure] benzene ring carrying a C(=O)-OH group and, on the adjacent (ortho) ring carbon, OH
        • C. [structure] benzene ring carrying a C(=O)-ON group and, on the adjacent (ortho) ring carbon, OH
        • D. [structure] benzene ring carrying a carbon bearing three OH groups and, on the adjacent (ortho) ring carbon, Br
        Answer, explanation and textbook page: open in the app.
      Which of the following is an acceptable IUPAC name for the organic compound shown below? [Figure: A scanned skeletal (zig-zag) structure of a carboxylic acid, drawn left to right. At the far left a carbon bears two methyl groups drawn as short bonds going up-left and down-left (an isopropyl end). From that branch carbon the chain zig-zags right through four further vertices (up, down, up, down) and ends at a carbon that carries a double-bonded O drawn above it and a bond to the right to the label OH. Counting the branch carbon plus one of its two methyls into the longest chain gives an eight-carbon acid chain with a methyl substituent on the carbon next to the far end.
      1. 64.No numbers, stereochemistry or other labels are drawn.]
        • A. Octanoic acid
        • B. 7-methyl heptanoic acid
        • C. - methyl heptanoic acid
        • D. 7 - methyl octanoic acid δ
        Answer, explanation and textbook page: open in the app.
      2. 65.Which of the following describes the balanced molecular equation when perchloric acids is mixed with solid iron (III) hydroxide?
        • B. HCl (aq) + Fe(OH) (s) →H O (I) + FeClO (aq) 4 3 2 4 3HClO (aq) + Fe(OH) (s) →3H O (l) + Fe(ClO ) 4 3 2 4 3
        • D. 3HOClO (aq) + Fe(OH) (s) →3H O (I) + Fe(ClO ) (aq) 2 3 2 3 3HOClO (aq) + Fe(OH) (s) →H O (l) + Fe(ClO ) ( 2 3 2 3
        Answer, explanation and textbook page: open in the app.
      3. 66.At 298 K the following two gaseous equilibrium involving and are established. SO (g) + 1/2 O (g) ⇌SO ; K1 2 2 3 2SO (g) ⇌2SO (g) + O (g); K2 3 2 2 Which of the following equilibrium expression is correct? 2 K = K 1 2 K = K 2 1
        • B. 2 K K = 1/K = 1/K
        • D. 2 1 2 1
        Answer, explanation and textbook page: open in the app.
      4. 68.for solid to liquid transitions for compound A is 2.73Kcal/mol and for compound B is 3.0 Kcal/mol. The melting point 0 C 0 30 C 0 ΔS A ΔS B for compound A is and the melting point for compound B is . the entropy changes and at the two transition temperatures are related as ΔS A ΔS B ΔS A ΔS B ΔS B ΔS A ΔS A 300ΔS /273 A
        • A. ?=
        • B. ᓼ<
        • C. ᓸ ᓸ<
        • D. ᓼ =
        Answer, explanation and textbook page: open in the app.
      5. 69.Which of the following metals forms a volatile compound that is taken as an advantage for its extraction?
        • A. CO
        • B. Fe
        • C. Ni
        • D. W
        Answer, explanation and textbook page: open in the app.
      6. 70.A 0.1M solution of HCl is dissolved in water. What species of ions are present at equilibrium, and what will be their equilibrium concentrations? [H O ] = 3 + 0.1M [OH ] = − 10 M −13 [Cl ] = − 0.1M [H O ] = 3 + 0.1M [OH ] = − 0.1M [Cl ] = − 0.1M
        • B. [H O ] = 3 + 0.1M [OH ] = − 10 M −13 [Cl ] = − 0M [H O ] = 3 + 10 M −13 [Cl ] = − 0.1M [OH ] = − 0.1M
        Answer, explanation and textbook page: open in the app.
      7. 71.The following bases and their conjugate acids (as the chlorides) are available in the laboratory: ( ), C H NCH CH NH 6 5 3 2 2 K = b 6.4 × 10−4 CH NH 3 2 K = b 4.4 × 10−4 ( ) and ( ). Which of these acid-base pairs are the best to prepare a buffer solution having a PH of about 9?
        • A. + conjugate acid
        • B. + conjugate acid NH 3 C H N 6 5 CH
        • C. + conjugate acid
        • D. + conjugate acid 3 2 CH NH CH NH 3 2 2
        Answer, explanation and textbook page: open in the app.
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