F.Sc.2.Chemistry.Ch.6.Test Solved - Malik Xufyan Cell # 0313-7355727

1. F.sc.2.Chemistry.Ch.05. Solved Test (Malik Xufyan)
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Name: Class: 12 Portion Inorganic
Paper: Chemistry Subjective Part Marks: 68
Time: 2:40 Test: 16 Chapter no: 6
SECTON –I
Q 2. Give the short answers of the any EIGHT questions.
16
i. Differentiate b/w typical and non-typical elements.
Sr # Typical elements Non-typical elements
1. Elements which show typical properties of
transition elements are called typical
transition elements.
Elements which do not show typical
properties of transition elements are
called non-typical transition elements.
2. For example Coinage metals include Cu,
Ag and Au. These are typical transition
elements because Cu2+
has 3d9
configuration, Ag2+
has 4d9
configuration
and Au3+
has 5d8
configurations.
For example Group llB include Zn, Cd
and Hg. These elements do not have
partially filled d-orbital in atomic state or
in their ionic state. Moreover, these
elements do not show typical properties
of transition elements except complex
formation.
ii. Give the some properties of transition elements.
Properties of transition elements are
 They are all metals. Some are very important in industry e.g. Ti, Fe, Cr, Ni, Cu, Mo,
Zr, Nb, Ta etc.
 They are hard with high melting and boiling points.
 They are good conductors of heat and electricity.
 Generally, they show variable valency.
 They form alloys with one another and with other elements.
iii. What do you know about the Oxidation states of transition elements?
Transition elements show variable oxidation state. It is because d-electrons of inner d-orbital
are also involved in bonding in addition to outer s-electrons. Due to the presence of large
number of unpaired electrons these can show variable valency. For higher oxidation states, d-
orbital involve in bonding. +2 oxidation state is produced due to the involvement of s-
electrons in bonding.
iv. Differentiate b/w paramagnetic and diamagnetic substances.
Sr # Paramagnetic substances Diamagnetic substances
1. Substances which are weakly
attracted by strong magnetic field are
called paramagnetic substances.
Substances which are weakly repelled by
strong magnetic field are called
diamagnetic substances.
2. The paramagnetic behavior is caused
by Unpaired electrons. It is because
moving electrons have magnetic
moments.
When electrons are paired, their magnetic
moments cancel the effect of each other
thus the substances becomes diamagnetic.

2. F.sc.2.Chemistry.Ch.05. Solved Test (Malik Xufyan)
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v. What is meant by interstitial compounds?
 Transition elements have close packed structure in which interstices are present.
 Small non-metallic atoms like H, B, C and N can enter into these interstices and
absorbed on the surface of metal atoms to form interstitial compounds.
 These compounds are non-stichiometric in nature and do not obey the laws of
chemical combination.
 Sometimes they are also called interstial alloys.
vi. What is meant by wrought iron?
It is the purest form of commercial iron. It has the lowest percentage of carbon. It has upto
0.3% impurities like S, P, Si, Mn etc.
S = 0.2 to 0.15%, Mn = upto 0.25%, P = 0.04 to 0.2%
vii. What is meant by corrosion? Explain.
The process of chemical decay of metals due to the action of surrounding medium is called
corrosion.
When metals come into contact of atmospheric gases, the surface of metals is coated with
oxides, sulphides, carbonates etc. sometimes these compounds form a compact layer on the
surface. Thus metal is protected from further attack.
However, if water is present in layer of oxides, sulphides and carbonates are dissolved in
water. Thus corrosion penetrates into metal.
viii. Give the preventive measure of corrosion.
Following measure or methods are used to prevent the metals from corrosion.
Coating of metals:
It is the simple method. In this metal surface is coated with oil, paints or enamels.
Alloying:
Corrosion can be prevented by alloying of metal with other metals. e.g. Corrosion of Fe is
prevented by alloying it with Ni, Cr etc.
Metallic coating:
A protective layer of another metal on the surface of metal can also prevent corrosion.
ix. What is meant by zinc coating?
It is done by dipping clear iron sheets in a ZnCl2 bath and heating. Iron sheets are removed
and rolled into Zn bath and air cooled.
If protective coating of Zn is destroyed then a galvanic cell is set up. In this cell Zn acts as
anode and iron acts as cathode. Electrons flow from Zn to iron. Thus Zn decays while Fe
remains intact. This is called sacrifical corrosion.
Fe2+
+ Zn Zn2+
+ Fe
This type of galvanizing is used in water pipes.
x. How prepared the potassium chromate?
Chromates of alkali metals are soluble in water. These are obtained by oxidizing trivalent
chromium compounds in the presence of an alkali.
2KCrO2 + 3Br2 + 8KOH 2K2CrO4 + 6KBr + 4H2O

3. F.sc.2.Chemistry.Ch.05. Solved Test (Malik Xufyan)
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Fusing Cr2O3 with an alkali in the presence of an oxidant, e.g potassium chlorate, can also
produce chromates.
Cr2O3 + 4KOH + KClO3 2K2CrO4 + KCl + 2H2O
xi. Give the systematic names of
(a) Fe(CO)5
Pentacarbonyl iron
(b) Na3[CoF6]
Sodium hexafluorocobalate (III)
(c) [Fe[H2O)6]2+
Hexaquairon (II) ion
xii. Explain the types of open hearth process.
There are following types of open hearth process;
1. If impurities are Mn, Si etc formed then furnace with acidic lining like SiO2 is used.
2. If impurities are P and S etc formed then furnace with basic lining like dolomite
(CaO, MgO) is used.
Q 3. Give the short answers of the any EIGHT questions.
16
i. Discuss the oxidizing property of potassium dichromate.
Dichromates are powerful oxidizing agents. Oxidation is carried out in an acid solution. In
this process, hexavalent chromium ion is reduced to trivalent chromium ion.
Reaction with Ferrous sulphate:
K2Cr2O7 + 7H2SO4 + 6FeSO4 K2SO4 + Cr2 (SO4)3 + 3Fe2(SO4)3 + 7H2O
ii. What is meant chromyl chloride test?
When solid potassium dichromate is heated with solid metal chloride in the presence of
concentrated sulphuric acid chromyl chloride is produced. This test is used for the detection
of metal chloride.
K2Cr2O7 + 6H2SO4 + 4NaCl 2KHSO4 + NaHSO4 + 2CrO2Cl2 + 3H2O
iii. Give the some uses of potassium dicchoromate.
 Potassium dichromate is used in dyeing.
 It is used in leather industries for chrome tanning.
 It is used as an oxidizing agent.
iv. Give the laboratory method of preparation of potassium permagnate.
It is prepared by acidifying the solution of potassium magnate, KmnO4 by H2SO4.
3K2MnO4 + 2H2SO4 2K2SO4 + 2KMnO4 + MnO2 + 2H2O
v. What is stadeler’s process?
In this method, Cl2 is passed through green solution of K2MnO4 until it becomes purple due
to the formation of KMn4. Hence Cl2 oxidizes K2MnO4 into KMnO4.
2K2MnO4 + Cl2 2KCl + 2KMnO4
vi. Give the physical properties of potassium permagnate.
 It forms dark purple lustrous crystals which gives deep pink color in solution.

4. F.sc.2.Chemistry.Ch.05. Solved Test (Malik Xufyan)
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 Its solubility in water at 20˚C is only about 7%. It dissolves more at higher
temperature (25% at 63˚C).
vii. Give some uses of potassium permagnate.
 Potassium permagnate is used as an oxidizing agent.
 It is used as a disinfectant and a germicide.
 It is used in the manufacturing of many organic compounds.
viii. Why does damaged tin plated iron get rusted quickly? Explain.
In tin plated iron a protective layer of tin is deposited on iron. If protective coating of tin is
damaged, then iron comes in contact with moisture of air. A galvanic cell is established in
which tin acts as cathode and iron acts as anode. The electrons flow from iron towards tin,
where they discharge H+
ions of moisture and leaving behind OH-
ions in solution.
ix. Give the construction of wrought iron from cast iron.
 It is manufactured from cast iron by puddling.
 In puddling cast iron is heated in a special type of reverberatory furnace called
puddling of furnace.
 Low roof of this furnace deflects hot gases and flames downwards and melts cast
iron.
 The hearth of furnace is lined with haematite (Fe2O3).
x. Give different types of steel.
There are three different types of steel.
Mild steel (0.1 -0.2%C)
 It is fairly soft malleable and ductile form of steel.
 It is used in making tubes, nuts, bolts, bars and boiler plates.
Medium carbon steel(0.2 – 0.7%C)
 It is harder than mild steel. It is malleable and ductile.
 It is used in making rails, axles castings.
High carbon steel(0.7 – 1.5%C)
 It is hard. It can be forged when % of carbon is less than 1.0%.
 It is used in making taps, cutting tools, machine tools hard steel etc.
xi. Draw structure of dioxalatoplatinate (II) ion.
When all the donor atoms of a polyhdrate ligand are coordinated with the same metal ion, a
complex compound is formed which contains one or more rings in its structure. The complex
compound formed called a chelate.
For example:

5. F.sc.2.Chemistry.Ch.05. Solved Test (Malik Xufyan)
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C
C
O-
O
O O-
C
C
O-
O-
O
O
Pt2+
2-
xii. How alloy is formed?
Transition metals of a particular series have almost similar sizes. Thus, these can replace
each other in crystal lattice to form substitutional alloys.
e.g. alloy steel is an alloy of iron with Cr, Mn and Ni. This alloys steel has many useful
properties. Other examples are brass, bronze, coinage alloys etc.
Q 4. Give the short answers of the any SIX questions.
12
i. Under what conditions does aluminium crude? Explain.
Aluminium corrodes only, when it is contact with those metals, which have greater reduction
potential than aluminium in the presence of moisture. In the presence of moisture if
aluminium is in contact with copper, silver or gold then Al is corroded. Thus, two conditions
are necessary for aluminium corrosion.
1. Moisture.
2. Contact with metals having greater reduction potential than aluminium such as copper,
gold and silver etc.
ii. How does the process of galvanizing protect iron from rustling?
The corrosion of iron can be prevented by galvanizing with zinc. It is done by dipping clear
iron sheets in a ZnCl2 bath and heating. Iron sheets are removed and rolled into Zn bath and
air cooled.
If protective coating of Zn is destroyed then a galvanic cell is set up. In this cell Zn acts as
anode and iron acts as cathode. Electrons flow from Zn to iron. Thus Zn decays while Fe
remains intact. This is called sacrificial corrosion.
Fe2+
+ Zn Zn2+
+ Fe
This type of galvanizing is used in water pipes.
iii. How chromate ions are converted into dichromate ions?
K2CrO4 and K2Cr2O4 show similar properties because in aqueous solution Cr2O7
2-
and CrO4
2-
ions exist in equilibrium.
2CrO4
2-
+ 2H+
Cr2O7
2-
+ H2O
iv. What do you know about ligands and chelates?
The atom or ion or neutral molecules which surround the central metal atom or ion by
denoting electron pairs are called ligands. For example: In K4[Fe(CN)6] and K3[Fe(CN)6] ,
CN-
is the ligand.
There are two types of ligands. These are Unidentate and polydentate ligands.

6. F.sc.2.Chemistry.Ch.05. Solved Test (Malik Xufyan)
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When all the donor atoms of a polydentate ligand are coordinated with the same metal ion, a
complex compound is formed which contains one or more rings in its structure. It is called a
chelate.
v. How does the electronic configuration of valance shell affecting the following
properties of the transition elements:
i) Paramagnetism.
Substances which are weakly attracted by strong magnetic field are called paramagnetic
Substances
Substances which are weakly repelled by strong magnetic field are called diamagnetic
substances.
The paramagnetic behavior is caused by unpaired electrons. It is because moving electrons
Have magnetic moments. When electrons are paired, their magnetic moments cancel the
effect of
Each other thus the substances become diamagnetic.
ii) Melting points.
Transition elements have very high melting points due to strong binding forces. Melting
points increases upto middle and then decreases to a minimum at the end of series. It is due to
increase in binding forces upto middle and then decrease upto end.
vi. Define coordination number and coordination sphere.
The number of lone pair of electrons provided by the ligands to the central metal atom or ion
is called the coordination number of the central metal atom or ion.
For example: in K4[Fe(CN)6], coordination number of Fe is 6.
The central metal atom or ion along with ligands is called the coordination sphere. Is placed
in square brackets. It may be anionic, cationic or neutral.
For example: in K4[Fe(CN)6, [Fe(CN)6]4-
is the anionic coordination number.
vii. How steel is manufactured? Explain.
Steel can be manufactured from cast iron by removing some carbon along with sulpher,
phosphorous and silicon.
It can be manufactured by adding required amount of carbon to wrought iron. Some special
constituents are also added e.g. tungsten, chromium, vanadium, molybdenum, manganese,
nickel and cobalt. These give desired properties to the steel.
At present most of the steel is manufactured from cast iron.
viii. How we construct the process Bessemer’s process?
The furnace called Bessemer’s converter.
It is a pear shaped vessel made of steel plates.
At the bottom of the converter there are numbers of holes through which hot air can be
introduced.
The converter is held on a central axis. It can be tilted for feeding and pouring out the
finished materials.
ix. How potassium dichromate is prepared? Just give equation.

7. F.sc.2.Chemistry.Ch.05. Solved Test (Malik Xufyan)
Cell # 0313-7355727
2CrO4
2-
+ 2H+
Cr2O7
2-
+ H2O
Na2Cr2O7 + 2KCl K2Cr2O7 + 2NaCl
SECTION-ll
Give the answers of the following three questions. Each question is of FOUR marks.
24
Q 5.A) Give details on nomenclature of complex compounds.
See the topic of nomenclature of complex compounds.
B) How steel is manufactured by open hearth and Bessemer process?
See the topic of manufacturing of steel.
Q 6.A) How electrochemical theory explain corrosion?
See the topic of corrosion.
B) Discuss the following properties of transition elements:
i) Binding energies ii) Covalent and atomic radii
See the topic of properties of transition elements.
Q 7.A) How wrought iron is manufactured from cast iron?
See the topic of wrought iron.
B) What is meant by complexes of compounds and their components? Explain.
See the topic of complex compounds.