Q62 of 312 Page 224

The solid element A exhibits the property of catenation. It is also present in the form of a gas B in the air which is utilized by plants in photosynthesis. An allotrope C of this element is used in glass cutters.

(a) What is element A?


(b) What is the gas B?


(c) Name the allotrope C.


(d) State another use of allotrope C (other than in glass cutters)


(e) Name another allotrope of element A which exists as spherical molecules.


(f) Name a yet another allotrope of element A which conducts electricity.

(a) Element A is carbon.

(b) The gas B is carbon dioxide (CO2).


(c) The allotrope C is diamond.


(d) Allotrope C is used for making jewellery.


(e) Buckministerfullerence is also allotrope of carbon which exists as spherical molecules.


(f) Graphite is an allotrope of carbon which conducts electricity.



More from this chapter

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60 A solid element X has four electrons in the outermost shell of its atom. An allotrope Y of this element is used as a dry lubricant in machinery and also in making pencil leads.

(a) What is element X?


(b) Name the allotrope Y?


(c) State whether allotrope Y is a good conductor or non-conductor of electricity.


(d) Name one use of allotrope Y (other than lubrication and pencil leads)


(e) Name two other allotropes of element X.

 61 Two organic compounds A and B have the same molecular formula C6H12. Write the names and structural formulae:

(a) if A is cyclic compound


(b) if B is an open chain compound


(c) Which compound contains single bonds as well as a double bond?


(d) Which compound contains only single bonds?

 63 An element E exist in three allotrope forms A, B and C. in allotrope A, the atoms of element E are joined to form a sheet like structure. In allotrope B, each atom of element E is surrounded by four other E atoms to form a rigid structure.

(a) Name the element E.


(b) What is allotrope A?


(c) What is allotrope B?


(d) What is allotrope C?


(e) Which allotrope is used in making jewellery?


(f) Which allotrope is used in making anode of a dry cell?

 64 You are given the following molecular formulae of some hydrocarbons:

C5H8; C7H14; C5H10; C7H12; C6H12;


(a) Which formula represent cyclohexane as well as hexane?


(b) Which formula represent benzene?


(c) Which three formulae represent open chain


(d) Which two formulae represent unsaturated hydrocarbons having double bonds?


(e) Which three formulae can represent cyclic hydrocarbons?