Board Paper of Class 12-Science 2007 Chemistry (SET 1) - Solutions
(i) All questions are compulsory.
(ii) This question paper consists of four sections A, B, C and D.
Section A contains 5 questions of one mark each.
Section B is of 7 questions of two marks each.
Section C is of 12 questions of three marks each and
Section D is of 3 questions of five marks each.
(iii) There is no overall choice. However, an internal choice has been provided.
(iv) Wherever necessary, the diagrams drawn should be neat and properly labelled.
- Question 1
What is the coordination number in a rock-salt type structure?VIEW SOLUTION
- Question 2
State Raoult’s law for a binary solution containing volatile components.VIEW SOLUTION
- Question 3
What is meant by order of a reaction being zero?VIEW SOLUTION
- Question 4
Write the IUPAC name of the following compound:
- Question 5
Mention one commercial use of N, N-Dimethyl aniline (DMA).VIEW SOLUTION
- Question 6
State as a mathematical formula the de Broglie relationship for moving particles. What experimental evidence is available for this concept?
Specify the ranges of values for quantum numbers mland msfor an electron in an atom when the nquantum number value for it is 2. What is the significance of these values for the orbitals?VIEW SOLUTION
- Question 7
When can an endothermic process be spontaneous? Give an example of such a process.VIEW SOLUTION
- Question 8
Write balanced chemical equations for the following reactions:
- Question 9
Explain any one of the following statements:
(i) The transition metals are well known for the formation of interstitial compounds.
(ii) The largest number of oxidation states are exhibited by manganese in the first series of transition elements.VIEW SOLUTION
- Question 10
Draw the three-dimensional representations of (R) - and (S) - butan- 2- ol.VIEW SOLUTION
- Question 11
Write chemical reaction equations to illustrate the following reactions:
(i) Williamson synthesis of ethers
(ii) Reimer−Tiemann reactionVIEW SOLUTION
- Question 12
Distinguish between addition polymers and condensation polymers and give one example of each class.VIEW SOLUTION
- Question 13
Answer the following in the light of MO theory:
(a) Which has a higher bond order, C2 or ?
(b) Which species is not likely to exist, Li2 or Be2?
(a) Compare the structural shapes of the following species:
SF6 and SF4
(b) What type of intermolecular forces exists between Cl2 and CBr4 present in a mutual solution?VIEW SOLUTION
- Question 14
(a) Name an element with which silicon can be doped to give an n-type semiconductor.
(b) Which type of crystals exhibits piezoelectricity?VIEW SOLUTION
- Question 15
The vapour pressure of water is 12.3 kPa at 300 K. Calculate the vapour pressure of a one molal solution of a non-volatile non-ionic solute in water.VIEW SOLUTION
- Question 16
Using the values of ΔfHΘand ΔrSΘ, given herein, calculate the standard molar Gibbs energy of formation, (ΔfGΘ) for CS2(l).
- Question 17
The rates of most reactions double when their temperature is raised from 298 K to 308 K. Calculate activation energy of such a reaction.
(R = 8.314 J mol−1K−1, log 2 = 0.3010)VIEW SOLUTION
- Question 18
State what is observed when
(i) the electrodes connected to a battery are dipped into a sol.
(ii) an electrolyte solution is added to a sol.
(iii) an emulsion is subjected to high-speed centrifugation.VIEW SOLUTION
- Question 19
Answer the following questions:
(i) Which element in the first series of transition elements does not exhibit variable oxidation states and why?
(ii) What happens when a solution of copper (II) sulphate is saturated with ammonia?
(iii) Why do actinoids, in general, exhibit a greater range of oxidation states than lanthanoids?VIEW SOLUTION
- Question 20
(a) Illustrate the following with an example each.
(i) Linkage isomerism
(ii) Coordination isomerism
(b) Why is paramagnetic? (Ni = 28)VIEW SOLUTION
- Question 21
Write the nuclear reactions for the following radioactive changes:
(i) undergoes α-decay
(ii) undergoes β-decay
(iii) undergoes K-decay
(You can put ‘X’ for the symbol which is not correctly known)VIEW SOLUTION
- Question 22
Explain the mechanism of nucleophilic addition to a carbonyl group and give one example of such addition reactions.VIEW SOLUTION
- Question 23
Write the chemical equations for the following chemical reactions:
(a) 1-Nitropropene is prepared from acetaldehyde
(b) Benzonitrile is converted into acetophenone
(c) A primary amine is prepared from a primary alkyl halideVIEW SOLUTION
- Question 24
Mention one important use of each of the following:
(iii) Carbon fibresVIEW SOLUTION
- Question 25
(a) Write the formulation for the galvanic cell in which the reaction,
Identify the cathode and the anode reactions in it.
(b) Write Nernst equation and calculate the emf of the following cell:
(a) Explain with one example each the terms weak and strong electrolytes.
(b) Write the Nernst equation and calculate the emf of the following cell:
- Question 26
(a) How would you account for any two of the following:
(i) PbO2 is a stronger oxidising agent than SnO2
(ii) H3PO2 acts as a monobasic acid.
(iii) The pKa value for HOCl is higher than that of HOClO
(b) Draw the structures of the following species:
(i) Peroxodisulphuric acid, H2S2O8
(ii) Xenon tetrafluoride, XeF4
(a) Assign reasons for any two of the following observations:
(i) The lower oxidation state becomes more stable with increasing atomic number in Group 13.
(ii) Hydrogen iodide is a stronger acid than hydrogen fluoride in aqueous solution.
(iii) The basic character among the hydrides of Group-15 elements decreases with increasing atomic numbers.
(b) Draw the structural formula for XeOF4.VIEW SOLUTION
- Question 27
(a) Name the three major classes of carbohydrates and give the distinctive characteristic of each class.
(b) What are nucleotides? Name two classes of nitrogen-containing bases found amongst nucleotides.
(a) Describe the classification of lipids based on their chemical compositions. Mention the chief chemical characteristic of each class.
(b) Explain the term ‘mutarotation’.VIEW SOLUTION