Test Papers / Previous Question Papers of Indira Gandhi National Open University CHE2 Inorganic Chemistry June 2006

Bachelor of Science (BSc)
Term-End Examination
CHEMISTRY

CHE2: Inorganic Chemistry

Time: 2 hours
Maximum Marks: 50

Note : (i) Answer all the five questions. Take particular care to note the internal choice in each question.
(ii) All the questions carry equal marks.

1. Answer any ten of the following (1x10):

(i) What is the atomic number of third alkaline earth metal, Be being the first member?

(ii) Arrange the following elements in the increasing order of ionisation energy: Na, Li, Rb, K

(iii) From among the following, choose the correct value for the principal quantum number of the outermost electron of potassium: 2,3,4,5,6

(iv) Arrange the following salts in the increasing order of lattice energy: KCl, LiCi, NaCl

(v) Choose the most basic hydroxide amongst the following: Be(OH)₂, BBr₃, BCl₃

(vii) Which gets more readily hydrolysed: CCl₄ or SiCl₄

(viii) Arrange the following in decreasing order of bond angle: NH₃, SbH₃, PH₃, AsH₃

(ix) Give the oxidation state of 'P' in H₃PO₄

(x) Arrange the following in increasing order of thermal stability: H₂O, H₂Te, H₂Se, H₂S.

(xi) Which one of the following has the highest electron affinity: F, Cl, Br, I

(xii) What is the state of hybridisation of Xe in XeF₄?

(xiii) What is the coordination number of Pt in the following compleX: [Pt(en)₂Cl₂]

(xv) Which metal is purified by Mond's process?

2. (a) Explain the basis on which elements are arranged in the long form of periodic table. (2)

(b) Define electron affinity. How does it vary across the period and down the group? (2)

(c) Define hydrogen bonding. Give its types. Water has abnormally high boiling point comared to the hydrides of other elements in Group 16. Explain. (4)

OR

What are the factors which influence solubility of a salt? Explain taking the example of caesium halides or alkali metal carbonates.

(d) Explain, with balanced equations, as to what happens when CO₂ is passed through lime water

(i) in small amounts,
(ii) in excess. (2)

OR

Why do alkaline earth metals form more complexes as compared to alkali metals?

3. (a) Write short notes on any two of the following: (3x2)

(i) Froth flotation method
(ii) Nitrogen cycle
(iii) Catenation property of carbon
(iv) Structure of diborane

(b) Answer (1) or (2) from the following : (4)

(1) Explain any two of the following
(i) Phosphorus forms PF5 while nitrogen does not form NF₅.
(ii) Boron forms electron-deficiet compounds.
(iii) Hydrolodic acid acts as a stronger acid than hydrochloric acid.

(2) Complete the following reactions (4)

(i) NH₃ + NaOCl
(ii) Zn + H₂SO₄
(iii) Na₂S₂O₃ + I₂
(iv) Cl₂+H₂S

4. (a) Give one reaction each to show the oxidising and reducing property of HNO₂. (2)

OR

Compare the structure of CO₂ and SiO₂.

(3) Discuss the structure of XeF2 or anhydrous aluminium chloride.

(c) Why is the bond dissociation energy of fluorine less than that of chlorine? (2)

OR

Discuss the diagonal relationship between boron and silicon. (2)

(d) What are interhalogen compounds ? How are they classified ? Give the structure of IF₇. (4)

OR

What are f-block elements ? Compare the properties of lanthanides and actinides.

5 . (a) Write chemical formula of any one of the following:

(i) Calcium hexacyanoferrate (II)
(ii) Potassium hexacyanocobaltate (III)

(b) Write the name of any one àf the following: (1)

(i) K₂[Ni(CN)₄]
(ii) [Pt(NH₃)₄(Cl)₂] SO₄,

(c) Using valence bond theory, predict the geometry and magnetic character of [NiCl₄]₂^-.(2)

OR

Give the postulates of Werner’s theory.

(d) Discuss any two of the following characteristics of d-block elements : (2x2)

(i) Variable valency
(ii) Magnetic property
(iii) Catalytic property
(iv) Complex formation

(e) Halogens form various types of compounds with oxygen. Is it justified to call them halides of oxygen ? Give reason for your answer. (2)

OR

Why is SO₃ not dissolved in water directly during the preparation of sulphuric acid?