SAMPLE QUESTION PAPER (2021-22)
CHEMISTRY (043)
TERM II
CLASS 12
Time: 2 Hrs Max. Marks: 35
GENERAL INSTRUCTIONS
1. There are 12 questions in this question paper with internal choice.
2. SECTION – A, Q. No. 1 – 3 are very short answer questions carrying 2 Marks each.
3. SECTION – B, Q. No. 4 – 11 are short answer questions carrying 3 Marks each.
4. SECTION – C, Q. No. 12 is case based question carrying 5 Marks.
5. All questions are compulsory.
6. Use of log tables and Calculator is not allowed.
SECTION A
Attempt all questions: –
Q1. Calculate the degree of dissociation (α) of acetic acid if its molar conductivity (Ʌm) is 39.05 S cm2 mol-1 given: λ0 (H+) = 349.6 S cm2 mol-1 and λ0 (CH3COO–) = 40.9 S cm2 mol-1
Q2. Write a chemical equation each to represent
(a) Gatterman reaction
(b) Carbylamine reaction.
Q3. Show the mechanism of acylation of Ethanamine and write IUPAC name of the product
formed.
SECTION B
Q4. Calculate the standard cell potential of the galvanic cell in which the following reaction
takes place:
2Cr (s) + 3Cd2+ (aq) —> 2Cr3+ (aq) + 3Cd (s)
Also calculate the ∆rG0 value of the reaction.
[Given: E0Cr3+/Cr) = – 0.74 V, E0Cd2+/Cd) = – 0.40 V and F = 96500 C mol-1]OR
The following chemical reaction is occurring in an electrochemical cell:
Mg (s) + 2Ag+(0.0001M) → Mg2+ (0.10M) + 2Ag (s)
The E0 electrode values are Mg2+/ Mg = -2.36 V, Ag+/Ag = 0.81 V
For this cell calculate:
(a) Standard cell potential (E0 cell)
(b) Cell potential (Ecell)
(c) (i) Symbolic representation of the above cell
(ii) Will the above cell reaction be spontaneous?
Q5. (a) For the following reaction: 2NO (g) + O2 (g) → 2NO2 (g),
Write the rate law and order of reaction.
(b) After 24 hours, only 0.125 g out of the initial quantity of 1 g of a radioactive isotope remains
behind. What is the half-life period?
OR
Following data are obtained for the reaction: N2O5 → 2NO2 + 1/2O2
(a) Show that it follows first order reaction.
(b) Calculate half-life period.
Q6. For the reaction:
Write:
(i) Rate reaction expression
(ii) Rate law equation.
(iii) Order and molecularity of the reaction.
Q7. Explain the following terms:
(i) Electrophoresis
(ii) Tyndall effect
(iii) Zeta potential
Q8. Explain the following observations:
(a) Ferric hydroxide sol gets coagulated on addition of sodium chloride solution.
(b) Cottrell’s smoke precipitator is fitted at the mouth of the chimney used in factories.
(c) Physical adsorption is multilayered, while chemisorption is monolayer.
Q9.
(a) For the complex [Fe (CN) 6]3-, write the hybridization type, magnetic character and spin
nature of the complex.
(b) Draw one of the geometrical isomers of the complex [Pt (en) 2Cl2]2+ which is optically
active.
OR
(a) Name the following compound according to IUPAC system of nomenclature:
[Pt (NH3)4 Cl (NO2)]SO4(b) On the basis of crystal field theory, write the electronic configuration for d4ion if ∆0 < P.
(c) Write the hybridization and magnetic behaviour of the complex [Ni (CN)4]2-
Q10. Write the products in the following reactions:
Q11. Complete the following sequence of reactions:
(i) Identify (A) to (D)
(ii) Give the IUPAC name of (A)
SECTION C
Q12. Case Based Question:
Read the passage given below and answer the following questions:
The d-block of the periodic table contains the elements of the groups 3–12 and is known
as transition elements. In general, the electronic configuration of the elements is (n-1) d1-10ns1-2. The d-orbitals of the penultimate energy level in their atoms receive electrons giving rise to the three rows of the transition metals i.e. 3d, 4d and 5d series. However, Zn, Cd and Hg are not regarded as transition elements. Transition elements exhibit certain characteristic properties like variable oxidation states, complex formation,
formation of coloured ions and alloys, catalytic activity, etc. Transition metals are hard
(except Zn, Cd and Hg) and have a high melting point.
The following questions ate multiple choice questions. Choose the most appropriate answer.
(i) The electronic configuration of d-block elements is
(a) (n-2) d1-10 (n-1)s1-2
(b) (n-1) d10ns1-2
(c) (n-2) d1-10ns1-2
(d) (n-1) d1-10ns1-2
(ii) Which transition element of 3d series does not show variable oxidation state?
(a) Chromium
(b) Titanium
(c) Scandium
(d) Mercury
(iii) Why are melting points of transition metals high?
(a) It is because of vacant d-orbitals.
(b) It is because of high ionization enthalpy.
(c) It is due to metallic bonding.
(d) It is because they occupy positions between s- and p-block.
(iv) 4d series of elements consists of the elements
(a) Sc – Zn
(b) Rf – Cn
(c) La – Hg
(d) Y – Cd
(v) Why are Zn, Cd and Hg not regarded as transition elements?
(a) They have low melting points.
(b) They have low boiling points.
(c) (n-1) d orbitals are completely filled.
(d) They do not show variable oxidation state.