Chemistry · Sample Paper 1

General instructions

Section A · Multiple choice

1. Question 14 marks

   The volume of 0.1 M $H_2SO_4$ needed to neutralise 20 mL of 0.2 M NaOH is

   1. A.10 mL
   2. B.20 mL
   3. C.40 mL
   4. D.5 mL
2. Question 24 marks

   Which set of quantum numbers describes the last electron of potassium (Z = 19)?

   1. A.$n=4, l=0, m_l=0, m_s=+\tfrac12$
   2. B.$n=3, l=2, m_l=0, m_s=+\tfrac12$
   3. C.$n=4, l=1, m_l=0, m_s=+\tfrac12$
   4. D.$n=3, l=1, m_l=1, m_s=-\tfrac12$
3. Question 34 marks

   The correct order of first ionisation enthalpy is

   1. A.B < Be < C < N
   2. B.Be < B < C < N
   3. C.B < C < Be < N
   4. D.N < C < Be < B
4. Question 44 marks

   Which species has the shortest bond length?

   1. A.$O_2$
   2. B.$O_2^+$
   3. C.$O_2^-$
   4. D.$O_2^{2-}$
5. Question 54 marks

   The shape of $ClF_3$ is

   1. A.trigonal planar
   2. B.T-shaped
   3. C.pyramidal
   4. D.see-saw
6. Question 64 marks

   For the reaction $C(s) + O_2(g) \to CO_2(g)$, $\Delta H$ and $\Delta U$ are related by

   1. A.$\Delta H = \Delta U$
   2. B.$\Delta H = \Delta U + RT$
   3. C.$\Delta H = \Delta U - RT$
   4. D.$\Delta H = \Delta U + 2RT$
7. Question 74 marks

   The pH of a buffer with 0.2 M $CH_3COOH$ and 0.02 M $CH_3COONa$ ($pK_a = 4.74$) is

   1. A.5.74
   2. B.3.74
   3. C.4.74
   4. D.2.74
8. Question 84 marks

   In the reaction $Cl_2 + 2OH^- \to Cl^- + ClO^- + H_2O$, chlorine is

   1. A.only oxidised
   2. B.only reduced
   3. C.both oxidised and reduced
   4. D.neither
9. Question 94 marks

   Which carbocation is the most stable?

   1. A.$CH_2=CH-CH_2^+$
   2. B.$C_6H_5CH_2^+$
   3. C.$(C_6H_5)_3C^+$
   4. D.$(CH_3)_3C^+$
10. Question 104 marks

    Propyne reacts with dilute H₂SO₄ in the presence of HgSO₄ to give

    1. A.propanal
    2. B.propanone
    3. C.propan-1-ol
    4. D.propanoic acid
11. Question 114 marks

    Which 0.1 m aqueous solution has the lowest freezing point?

    1. A.glucose
    2. B.KCl
    3. C.$K_2SO_4$
    4. D.urea
12. Question 124 marks

    For the cell $Zn|Zn^{2+}(0.01\,M)||Cu^{2+}(1\,M)|Cu$, $E^\circ = 1.10$ V. The emf at 298 K is

    1. A.1.04 V
    2. B.1.10 V
    3. C.1.16 V
    4. D.1.13 V
13. Question 134 marks

    The rate of a reaction doubles for every 10 °C rise. If the temperature rises from 20 °C to 50 °C, the rate increases

    1. A.3 times
    2. B.6 times
    3. C.8 times
    4. D.9 times
14. Question 144 marks

    Which oxoacid of phosphorus is a strong reducing agent?

    1. A.$H_3PO_4$
    2. B.$H_3PO_2$
    3. C.$H_4P_2O_7$
    4. D.$HPO_3$
15. Question 154 marks

    In acidic medium, $KMnO_4$ is reduced to

    1. A.$MnO_2$
    2. B.$Mn^{2+}$
    3. C.$MnO_4^{2-}$
    4. D.$Mn_2O_3$
16. Question 164 marks

    The number of geometrical isomers of $[Co(NH_3)_4Cl_2]^+$ is

    1. A.1
    2. B.2
    3. C.3
    4. D.4
17. Question 174 marks

    Which reaction converts an alkyl chloride into an alkyl iodide?

    1. A.Swarts
    2. B.Finkelstein
    3. C.Wurtz
    4. D.Sandmeyer
18. Question 184 marks

    Phenol reacts with bromine water to give

    1. A.o-bromophenol
    2. B.p-bromophenol
    3. C.2,4,6-tribromophenol
    4. D.bromobenzene
19. Question 194 marks

    Which is the strongest acid?

    1. A.$CH_3COOH$
    2. B.$ClCH_2COOH$
    3. C.$Cl_2CHCOOH$
    4. D.$Cl_3CCOOH$
20. Question 204 marks

    The Hoffmann bromamide reaction converts an amide into

    1. A.an amine with the same number of carbons
    2. B.an amine with one less carbon
    3. C.a nitrile
    4. D.an acid

Section B · Numerical value

1. Question 214 marks

   Find the mass in grams of $CO_2$ formed when 12 g of carbon burns completely in excess oxygen.

2. Question 224 marks

   A first-order reaction has a half-life of 30 min. Find the time in minutes for 75% completion.

3. Question 234 marks

   Find the number of unpaired electrons in $[Fe(CN)_6]^{3-}$.

4. Question 244 marks

   0.5 mol of a non-electrolyte is dissolved in 500 g of water. Find the elevation in boiling point in units of 0.01 K. ($K_b = 0.52$ K kg mol⁻¹)

5. Question 254 marks

   How many structural isomers (alkanes) have the formula $C_6H_{14}$?