QUESTION BANK – REPRESENTATIVE ELEMENTS
1) Describe the following in relation to group 13 elements (boron family) :
(i) Similarity between B and Si.
(ii) Tendency to form hydrides.
2) Discuss the trends in chemical properties of group 13 elements.
3) How is diborane prepared in the laboratory ? Give its structure.
4) a) Boron forms electron deficient compounds.
b) BF3 is a weaker Lewis acid than BC1
c) Anhydrous AlF3 has higher melting point than AlCI3.
d) Boron chloride exist as monomer while in the same group anhydrous aluminium chloride exists as dimer.
e) + I oxidation state of thallium (atomic No. 81) is more stable than its + 3 oxidation state.
f) As we move down in group 13 elements increase in atomic size is comparatively very less.
g) The first I.E. of B and Al is less than the first I.E. of Be and Mg.
h) Gallium has higher I.E. than Al. Explain.
i) BF3 is planer molecule but NH3 is pyramidal molecule.
5) Discuss the diagonal relationship of Be and Al with regard to (i) the action of alkali and (ii) the structure of the chlorides.
6)Present a comparative account of each of the following
- a) Structure of BCl3 and AlCI3
- b) Structures of BeCl2 and AlC13
- c) Lewis acid character of BF3 and BCI3.
7 )Draw the structure of diborane and describe in terms of multi-centre bonds.
8) Draw a labelled diagram to show the dimeric structure ofAI(lll) chloride. State one use of anhydrous AlCI3.
9 ) What is ‘inert pair effect’ ? Discuss the oxidation states of group 13 elements in relation lo inert pair effect.
10)Which one of the following elements exhibits + 1 oxidation state as
well : Al, B, Ca, Tl, Be ?
11) Between AIF3 and AlCl3 which one will have a higher melting point.
1) Account for the following :
a) Silane gets hydrolysed by water whereas alkanes do not.
b) SiC14 gets hydrolysed, CC14 does not.
c) PbC14 exists, PbBr4 and PbI4 do not.
d) Si has similar structure to diamond and not to graphite
e) Silicones are used in electronic and electrical appliances.
f) Graphite is better lubricant at moon than on the earth.
g) Why CO2 is a gas at room temperature while Si02 is high melting solid.
h) PbX2 is more stable than PbX4 [here X s Cl, Br, 1].
i) S ilanes get hydrolysed, whereas alkanes do not.
j) SnCI2 is good reducing agent.
k) SnCl2 is solid, SnCI4 is liquid .
l) Solid CO2 is called dry ice.
m) Tendency to show + 2 oxidation state increases with increasing atomic number in group 1
n) The + 4 oxidation state becomes less stable down in group 14 .
0) PbO4 is stronger oxidizing agent than SnO4 .
p) CC14 remains unaffected whereas SiC14 gets hydrolysed.
q) Elemental silicon does not form graphite like structure as the carbon does.
2) a) Arrange the hydrides of group 14 in increasing order of thermal stability.
b) Arrange the hydrides of group 14 in increasing order of reducing power.
3) What are silicones ? Give commercial method for their preparations.
4) Give a comparative account of the chemistry of carbon and silicon with regard to their
(i) property of catenation and (ii) stability of hydrides and oxides.
(iii) Oxidation state of tin and lead
5) ) Discuss how docs carbon differ from other elements of group 14 with regard to (a) catenation
(b) formation of oxides
6) Write two commercial methods for preparation of silicon.
- Arrange the following in decreasing order of boiling point giving reason ;
CH4, S iH4, GaH4, SnH4.
8) What is meant by catenation ? How does catenation tendency for elements of group 14 vary?
9) Present a comparative account of following;
- a) A ction of water on CC14 and SiC14
- b) Structures of CO2 and SiO2
10) Define catenation and illustratewilh an example. Describe briefly the properties of group 14 elements (carbon family).
11) What are silicones ? How are they manufactured ?
1) Give reason for the folowing:
1) The maximum number of covalent bonds formed by nitrogen is 4.
2) NO2 readily forms a dimer.
3) Phosphuric acid is syrupy.
4) Nitrogen is a gas whereas Phosphorus is solid
5) In trimethyl amine, the nitrogen has a pyramidal geometry whereas in trisilylamine N(SiH3)3, it has a planer geometry
6) N2 molecule is chemically inert while white phosphorus is more reactive.
7) NH3 is a good complexing agent.
8) Nitrogen forms a large number of oxides than posphorus .
9) Nitrogen exists as diatomic molecule (N2) whereas phosphorus exists as tetra atomic (P4) molecule
10) NF3 is an exothermic compound but NCI3 is an endothermic compound.
11) Nitrogen does not form pent a chloride by phosphorus form.
12) Nitric acid becomes yellow in colour on long standing
13) The first ionisation energy of nitrogen is greater than oxygen.
14) NH3 is more basic than phosphine
15) Acidity of oxyacids of nitrogen increases with increase in oxidation state
16) BF3 is planer molecule but NH3 is pyramidal molecule.
17) NCl3 & PCl3 gives different products on hydrolysis
18) H3PO4 & H3PO3 both contains three hydrogen but H3PO4 is triprotic but H3PO3 is diprotic.
19) Thermal stability of gr .15 hydrides decreases down the group.
20) PF6– is octahedral .
21) Pent halides of gr.15 acts as Lewis acid.
22) Basic strength of gr 15 hydrides decreases down the group.
23) Solubility of gr 15 hydrides decreases down the group.
24) SbF5 is known bu BiF5 is not Known.
25) There is a considerable increase in covalent radius from N to P but from As to Bi onlya small
change is observed.
26) Ionic radius of Sb and Bi are very less when compared to the ionic radius of N,P and As.
27) Metallic character of group 15 elements increases on going down the group.
29) Tendency to show – 3 oxidation states in group 15 decreases on going down the group.
30) The oxides in higher oxidation states of group 15 elements are more acidic than that of lower
31) PCl5 is more covalent than PCl3.
32) PCl5 is more covalent than PF5.
33) All the five bonds in PCl5 are not equivalent.(Or) PCl5 is more reactive than PCl3.
34). Both PCl3 and PCl5 fumes in air.
35) Aluminium is rendered passive in concentrated HNO3.
36) HNH bond angle in NH3 is less than the tetra hedral bond angle of 109.50.
37) Bond angles of HPH,HAsH and HSbH are closer to 900.
38) H3PO2 is a good reducing agent.
39) CN- is known but CP- is not known.
2) Present a comparative account of following:
1) Proton affinity of NH3 and PH3
2) Physical state of nitrogen and phosphorous
3) Basic properties of NH3 and PH3
3) a) Why does nitrogen show anomalous behavior as compared to other members of this group?
b) Give five points of differences between nitrogen & other members of the group.
4) Give a comparative account of chemistry of hydrides (stability and basic character) and halides (MX3 and MX5types) of N and P.
5) Arrange the following in decreasing order of property indicated :
- a) NH3, PH3, AsH3, SbH3, base strength.
- b) NF3, PF3, AsF3, BiF3. Ionic character Give reasons
- c) NH3, PH3, AsH3, SbH3 , BiH3 -Stability of hydrides
- d) NH3, PH3, AsH3, SbH3 ,BiH3 -Reducing character of hydrides
6) Give three oxo-acids of nitrogen. Write the oxidation state of nitrogen in each of them.
7) Discuss the following properties of group 15 elements:-
1) Hydroxide formation
2) Hydride formation
3) Halide formation
4) Oxidation States
5) Acidity of oxides.
8) Discuss the following trends of group 15 hydrides:-
- a) Solubility
- b) Thermal stability
- c) Basic Strength
- d) Reducing properties.
9) Give the structure the following compounds of nitrogen & state the oxidation state of nitrogen in each
of them. NH3, N2H4, NH2OH, HNO3, N2O, NO2, N2O4, N2O3, N2O5.
10) Give the structure the following compounds of phosphorous & state the oxidation state of
Phosphorous in each of them. PCl5, PCl3, H3PO4, H3PO3, H3PO2, P203, P2O5, P4, PH3,
H4P2O7, P4O6, P4O10.
11) A white waxy solid A on heating in an inert atmosphere forms its allotrope B. A reacts with concentrated alkali to form a toxic gas C. A reacts with excess of chlorine to give D. D on hydrolysis gives an acid E. Identify the compounds. Write the reactions involved.
1) Compare and contrast the following :
(a) Maximum covalency ofoxygen and sulphur.
(b) Bond angles of H2O and H2S
1) Oxygen is gas while sulphur is a solid .
2) Sulfur disappears when boiled with sodium sulphite.
3) Oxygen-oxygen bond length in ozone is same.
4) H2O is liquid whereas H2S is gas at room temperature
5) Oxygen does not show an oxidation state of+ 4 and + 6 like sulphur
6) The tendency to show – 2 oxidation state diminishes from sulphur to polonium
7) Binary compounds of oxygen and fluorine be called oxygen fluorides and not fluorine oxide
8) Sulfur is a solid but Oxygen is a gas at room temperature.
9) Oxygen shows covalency of, but sulfur shows a covalency of 6
10) H2S is a stronger reducing agent than H2O.
11) SF6 is known but OF6 is not known.
12) SF6 is known but SH6 is not known.
13) Group 16 elements are called calcogen.
14) Tendency to exhibit -2 oxidation state decreases from S to Po.
15) Reducing power of gr -16 hydrides is as follows: H2Te>H2Se> H2S>H2O.
16) Order of acidity of gr -16 hydrides is as follows: H2Te>H2Se> H2S>H2O.
17) The decreasing order of boiling point of group 16 hydrides is as follows:
H2O. >H2S> H2Se >H2Te
18) Group 16 elements called chalcogens
19) Sulphur has very high boiling and melting point when compared to oxygen.
20) In group 16 tendencies to show -2 oxidation state decreases on going down the group.
21) In group 16 +4 oxidation state become more stable than +6 oxidation state on going down the group.
22) Oxygen can show a maximum covalency of 4 and it can not form hexa valent compound.
23) SF6 is exceptionally stable or it can not be hydrolysed easily.
25) MnO is basic while Mn2O7 is acidic.
25) O3 is thermo dynamically unstable than O2 (or) . O3 in higher concentration is explosive.
26) HCl and HNO3 are prepared by reacting NaCl and NaNO3 respectively with H2SO4 while HBr and HI can’t be prepared by this method.
27) Cane sugar chars in concentrated sulphuric acid.
28 ) Concentrated sulphuric acid is a good oxidizing agent.
29) Two S-O bonds in SO2 are equivalent.
30) Ka2 of H2SO4 is << Ka1.
3) Describe the trends of the following properties of gr-16 elements:-
1) Metallic Character
2) Stability of hydrides
4) Acidic Character
5) Capacity to form hydrides
6)Tendency of forming oxyacids
8) Oxidation State
4)) Compare the structure of :-
1) SO2 & SO3 2) SO3 & SeO3
5) Write the chemical formula and structure of the following oxyacids of sulfur . state the oxidation state of sulfur in each of them:-sulphuric acid, sulphurous acid, thio sulphuric acid, peroxomonosulphuric acid , peroxodisulphuric acid , dithionic acid.
6) Give the structure of following compounds: SO3, SO2, S8, H2S, SF4, SF6.
7) Explain the hybridization in SF4, SF6 molecule. What is the shape of this molecule
8) State any four properties which make oxygen different from the rest of the elements of the same group. Give a reason for anomalous behavior of oxygen.
9) Concentrated sulphuric acid is added followed by heating to each of the following test tubes labelled (i) to (v)
Identify in which of the above test tube the following change will be observed. Support your answer with the help of a chemical equation.
- a) Formation of black substance
- b) Evolution of brown gas
- c) Evolution of colourless gas
- d) Formation of brown substance which on dilution becomes blue
- e ) Disappearance of yellow powder along with evolution of colourless gas.
10) An yellow colored solid A forms its hydride B. B has foul smell and extensively used in salt analysis. B on oxidation gives C. C further gets oxidized in the presence of a catalyst to give D. C decolorize acidified potassium permanganate. Identify the compounds. Write the reaction involved in the conversion of C to D and the reaction of C with acidified potassium permanganate solution.
11) What is disproportionation reaction? Give equation of the reactions involved in the disproportionation
Of a) HNO2 b) Se2Cl2 c) H3PO3
1) What is Freon ?
2) What are halogens and why are they called so ?
3) Which of the halogen is radioactive 7
4) Arrange the given halogens in increasing order of boiling point— F; CI; Br; I.
5) Arrange the halo acids in the increasing order of acidic character.
6) Name the oxides of chlorine that are used as bleaching agents for paper pulp.
7) Among halogen hydrides which has maximum per cent ionic character.
8) Write an example of a neutral molecule which is iso-electronic with CIO-.
9) Account for the following :
- 1. Fluorine always exhibit an oxidation slate of- I only .
- 2. Covalent bonding of halogens always sigma bonding .
- 3. Fluorine is most reactive among halogens .
- 4. Bond dissociation energy of F2 less than Cl2 .
- 5. I2 is more soluble in KI than in water .
- 6. F2O is referred to as a fluoride but C12O is an oxide .
- 7. HF in aqueous solution is stronger acidic than HCI.
- 8. HF is stored in wax-coated bottles.
- 9. Hydrogen fluoride has higher boiling point than hydrogen chloride.
- 10. Halogens shows different color.
- 11. HF is a weak acid in water but a strong acid in ammonia.
- 12. HF has low boiling point than HCl , HBr, HI
- 13. Electron affinity of Chlorine is more then Flourine.
- 14. Reducing power of gr 17 elements are as follows .HI>HBr>HCl>HF.
- 15. Acid strength of gr 17 elements are as follows .HI>HBr>HCl>HF.
- 16. Acid strength of oxo acids are as follows HClO4> HClO3>HClO2> HClO.
- 17. Acid strength of hypohalous acids are as follows HClO> HBrO>HIO.
- 18. In inter halogen compound of type AB5 & AB7 , B is invariably F .
- 19. Halogens are strong oxidizing agents.
- 20. All halogens are colored.
- 21, F2 has smaller enthalpy of dissociation than Cl2.
- 22. Fluorine has lesser negative value of electron gain enthalpy than chlorine but fluorine is a stronger oxidizing agent than chlorine.
- 23. Ionic character of halides MF>MCl>MBr>MI
- 24. In metal halides, halides in higher oxidation state of the metal is more covalent than the one in lower oxidation state.(PbCl4 is more covalent than PbCl2)
- 25. Chlorine is a powerful bleaching agent.
- 26. Fluorine forms only one oxo acid HOF
- 27. Acidity of oxo acids HClO4> HClO3> HClO2> HClO.
- 28. Acidity of oxo acids HOCl>HOBr>HOI
- 29. Oxidizing power of HClO4> HClO3> HClO2> HClO
10) How is bleaching powder prepared ? Mention two of its uses.
11) Give two compounds of halogens in which the halogens display different positive oxidation states.
12) Present a comparative account of following;
- a) Oxidizing power of Fa and CI;
- b) Acidic properties of HP and HCI
13) Draw the structure of IF& Iodine penta fluoride .
14) X2 is greenish yellow gas with an offensive smell used in water purifications. It partially dissolves in water to give a solution which turns blue litmus red. When X2; is passed through NaBr solution, Br2; is obtained. (a) Identify X2;. (b) Name the group to which does it belong
15) Describe briefly the properties of group 17 elements (halogen family).
- Non –Mettalic character,
- Acidic character of oxides,
- Stability and Acid character of their hydrides,
- Relative oxidizing power,
- Oxoacids and their relative oxidizing power.
16) Arrange the hydrides of halogen family in increasing order of
(a) ionic character (b) bond length
(c) thermal stability (d) dipole moment
(c) boiling point.
17) Arrange the different oxy acids of chlorine in increasing order of (a) thermal stability (b) oxidizingpower (c) acidic character.
18) Name the halogen hydride:- (i) forms H-bonding (ii) forms strongest acid
19 ) Name the halogen:- i) has highest ionization energy (ii) shows some metallic properties iii) has highest electron affinity ?
20 ) Describe the following about halogen family (group 17 elements) ;
(i) Relative oxidizing power
(ii) Relative strength of their hydrides
(iii) Oxy acids and their related oxidizing ability.
21) State two examples of the compounds in which halogen display positive oxidation states.
22) Write five points of similarities and differences between Flourine and rest of the gr . 17 elements. Give reasons for such differences.
23) What are polyhalides? Give examples.
24) What are pseudohalides? Give examples
1)) Which noble gas is radioactive ?
2)) Account for the following observations :
1) Noble gases have largest radii.
2) Helium is used for inflating aeroplane tyres.
3) Xe readily forms compounds but krypton does not form compounds easily.
4) Noble gases exist as monoatomic molecules.
5) Noble gases form compounds with fluorine and oxygen only .
6) Noble gases have low chemical reactivity.
7) Nobel gases are water soluble.
8) Group 18 elements are chemically unreactive.
9) Group 18 elements have very high ionization enthalpy and it decreases on going down the group.
10) Group 18 elements have positive value of electron gain enthalpy.
11) Group 18 elements have lower value of boiling and melting point and it increases on going down the group.
12) Group 18 elements have larger atomic radius.
13) Bartlett synthesized XePtF6 from his knowledge of earlier known compound O2PtF6.
14) Xenon forms noble gas compounds.
15) Xenon forms compounds only with oxygen and fluorine.
16) Helium is used in diving apparatus.
17) Oxygen has lesser negative value of electron gain enthalpy than Sulphur.
18) XeF, XeF3 and XeF5 not known.
3) What was the frist nobel gas compound? Give the reason which prompted Bartlett lo prepare first noble gas compounds.
4) Discuss the following trends of group 81 elements a0reactivity b) ionization energy
5) Write the preparation, properties and structure of the following Xenon compounds.
- i) XeF2 ii) XeF4 iii) XeF6 iv) XeO v) XeF4O vi) XeO3 vii) XeF2O2
6) Give the formula and structure of noble gas species which is iso structural with
- a) ICl4– b) IBr2– c) IF6– d) BrO3–