A certain salt X, gives the results Borax swells up to a glassy mass on strong heating.
Is swells up to a glassy material Y on strong heating

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(a)

Explain the following.
Aluminium forms [AlF₆]^3- ion but boron does not form [BF₆]^3-ion.

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Account for CO is poisonous.

4

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Account for CO₂ is used in refrigeration.

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What are electron deficient compounds? Are BCl₃ and SiCl₄ electron deficient species? Explain.

4

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Write the resonance structure of CO₃^2- and HCO₃^-.

4

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Explain the difference in properties of diamond and graphite on the basis of their structures.

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Explain structures of diborane and boric acid.

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Give one method for industrial preparation and one for laboratory preparation of co and co₂ each.

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If the starting material for the manufacture of silicons is RSiCl₃ write the structure of the product formed.

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Describe two similarities and two dissimilarities between B and AI.

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(a) What is general formula of silicons?
(b) How are linear silicons obtained?

4

(a)

What are Fullerenes? How are they prepared?

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Give reason.
(i) C and Si are always tetravalent but Ge, Sn, Pb show divalency.
(ii) Gallium has higher ionization enthalpy than AI. Explain.

4

(a)

Give reason why boron and aluminium tend to form covalent compounds

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