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SEKOLAH MENENGAH KEBANGSAAN SULTAN ISMAIL, JOHORBAHRUINORGANIC
CHEMISTRY/ UPPER SIX/ 2013TOPIC : GROUP 14 ELEMENTS
Exercise 5.1
1. Explain each of the following observations.(a) Carbon dioxide
is a gas at room temperature but silicon (IV) oxide is asolid
with
high melting point.
(b) When lead (IV) oxide is strongly heated, a colourless gas is
produced.No such gas is
produced when silicon (IV) oxide is heated.
(c) Silicon has a diamond-type structure, but is not as hard as
diamond.
2. The tetrachlorides of Group 14 elements are liquids at
roomtemperature. All the
tetrachlorides except CCl4 are hydrolysed by water to give
acidicsolutions.(a) State the shape of the group 14 tetrachlorides.
What type ofhybridization is present
in the group 14 atom.
(b) When tetrachloride has the lowest thermal stability? Explain
youranswer.
(c) Write equation for the hydrolysis of SiCl4
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(d) Explain why CCl4 does not undergo hydrolysis.
3. Freons are used as coolants in air conditioners and
regrigerators. Oneexample of
freons is trichlorofluoromethane.(a) Write the chemical formula
of a Freon other thantrichlorofluoromethane.
(b) State a property of freons that justifies its use as a
coolant.
(c) Name two reagents that can be used to
preparetrichlorofloromethane.
(d) Write an equation for the decomposition of
trichlorofluoromethaneinto the species
that are responsible for the destruction of the ozone layer in
thestratosphere.
4. A scheme of reaction is shown below : X(l) Y(s) + Cl2(g)
HCl(aq)
Tetrachloroplumbate (II) (aq)ion
(a) Identify compound X and discuss its chemical properties.
(b) Compound X is an only liquid while compound Y is a white
solid.
Explain thedifferent physical states of the two compounds.
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5. The two common oxides of lead are lead (Ii) oxide and leqd
(IV) oxide.Lead (II)
oxide dissolves readily in aqueous nitric acid. Lead (IV) oxide
reactswith
concentrated hydrochloric acid to form lead (II) chloride and
chlorine.
(a) Write a balanced equation for the reaction between lead (Ii)
oxide andaqueous
nitric acid.
(b) What is the property shown by lead (II) oxide in the
reaction in (a) ?
(c) Write a balance d equation to show the reaction between lead
(IV)oxide and
concentrated hydrochloric acid.
(d) state the change in oxidation number of lead in the reaction
in (c).
(e) What is the property shown by lead (IV) oxide in this
reaction?
(f) State the relative stability of lead (II) and lead (IV)
compounds.
