1.USES
1➤ Coordination compounds used in Medicine.
=> Ans. The complexes are used on a large scale in medicine. Many
medicines in the complex form are more stable, more effective and can be
assimilated easily. For example, platinum complex [Pt(NH),C1,] known as
cisplatin is effectively used in cancer treatment. EDTA is used to treat
poisoning by heavy metals like lead.
2➤ Write four uses of chlorine
=> For bleaching. For the preparation of insecticides. For removing
stains in the fabric. For purification of water. For the preparation of
bleaching powder.
3➤ Write three physical properties and three uses of sulfuric acid .
=> It is a common chemical in the preparation of fertilizers. For
example, ammonium sulfate and superphosphate. We use it in the
manufacture of dyes, shades, and paints. It is a common chemical in the
manufacture of explosives. For example, TNT. Other imperative chemicals
need the presence of sulfuric acid. Without sulfuric acid, we cannot get
these chemicals. For example, hydrochloric, phosphoric and nitric acid.
It is also needed for sodium carbonate. We utilise it as a part of the
refining of petroleum. It acts as a pickling agent. This chemical is
common as a laboratory agent, dehydrating agent and an oxidizing.
4➤ cast iron and wrought iron with their uses?
=> 1. Cast iron is hard and brittle and contains 4% carbon. Uses:
For making pipes, manufacturing automotive parts, pots, pans, utensils,
etc. 2. Wrought iron is very soft and contains less than 0.2% carbon.
Uses: For making pipes, bars for stay bolts, engine bolts, and rivets,
etc.
5➤ Coordination compounds used in Electroplating.
=> Ans. Electroplating involves deposition of a metal on the other
metal. For smooth plating, it is necessary to supply continuously the
metal ions in small amounts. For this purpose, a solution of a
coordination compound is used which dissociates to a very less extent.
For example, for uniform and thin plating of silver and gold, the
complexes K[Ag(CN)2] and K[Au(CN),] are used.
6➤ Coordination compounds used in the estimation of hardness of water.
=> Ans. (1) The hardness of water is due to the presence Mg2+ and
Ca2+ ion in water. (2) The strong field ligand EDTA forms stable
complexes with Mg2+ and Ca2+. Hence these ions can be removed by adding
EDTA to hard water. Similarly, these ions can be selectively estimated
due to the difference in their stability constants.
7➤ Methyl alcohol.
=> Ans. (1) Methyl alcohol is used as an industrial solvent for
dissolving oils, fats, gums, etc. (2) It is used for dry cleaning and
preparation of perfumes and varnishes. (3) It is used as antifreeze
agent for automobile radiators at low temperature. (4) It is used in the
preparation of methyl chloride, dimethyl sulphate and formaldehyde. (5)
It is used to denature ethyl alcohol.
8➤ Ethyl alcohol.
=> Ans. (1) Ethyl alcohol is used as solvent for dyes, oils,
perfumes, cosmetics and drugs. (2) A mixture of 10-20% ethyl alcohol
with petrol is used as motor fuel. (3) A mixture of ethyl alcohol and
calcium acetate in gel form is used as solid fuel. (4) It is widely used
in beverages. (5) Since ethyl alcohol has low freezing point, it is used
in thermometer. (6) It is an effective tropical antiseptic, therefore it
is used in many mouth washes. (7) It kills micro-organisms on wound
surface and in the mouth but its low toxicity does not kill the cells of
the skin or mouth tissues. (8) It is used in the preparation of
chloroform, iodoform, acetic acid and ethers. (9) It is used as
fuel.
9➤ Phenol.
=> (1) Phenol is used in the preparation of phenol-formaldehyde
polymer which is used in a plastic bakelite. (2) It is used in the
preparation of phenol-phthalein-an indicator and in certain dyes. (3) It
is used in the preparation of drugs such as salol, aspirin, etc. (4) It
is used in the preparation of dettol, which is an antiseptic. (5) It is
used in the preparation of 2, 4-dichlorophenoxy acetic acid which is
used as selective weed killer. (6) It is used to prepare picric acid
which is used as explosive
10➤ Ethers.
=> Ans. (1) Diethyl ether is used as industrial solvent for oils,
fats, gum, resin, etc. (2) It is used as solvent in the reaction of
Grignard reagent. (3) It is used as refrigerant. (4) Natalite, a mixture
of diethyl ether and ethyl alcohol is used as fuel.
11➤ uses of alloy.
=> It is used for making statues, medals, and trophies.
Cupra-nickel, an alloy of copper and nickel is used for making machinery
parts of marine ships, boats. For example, marine condenser tubes.
Stainless steels are used in the construction of the outer fuselage of
ultra-high-speed aircraft.
12➤ Write any two properties and uses of actinides.
=> The elements of Actinides are used as nuclear reactors and in
nuclear weapons. There are different uses of Uranium and Thorium. Some
of the elements in the actinides series are also used as smoke
detectors. The Actinides are typical metals and they have properties of
D block and F block elements.
13➤ uses of LDP.
=> It is mainly used in the preparation of pipes for agriculture,
irrigation, domestic water line connections as well as insulation to
electric cables. It is also used in submarine cable insulation.
14➤ nylon 6,6
=> Nylon-6,6 is prepared by the method of condensation
polymerisation process. Hexamethylenediamine combines with adipic acid
to give the macromolecule Nylon-6,6 with the elimination of water
molecule. Used in making sheets, bristles for brushes and in the textile
industry.
15➤ high density polythene
=> HDP is used in the manufacture of toys and other household
articles like buckets, dustbins, bottles, pipes, etc. b. It is used to
prepare laboratory wares and other objects where high tensile strength
and stiffness is required.
16➤ Give examples of industrial application of enzyme catalysis.
=> Ans. (1) Glucose Isomerase (enzyme) is used in conversion of
glucose to sweet-tasting fructose. (2) New antibiotics are manufactured
using penicillin acylase (enzyme). (3) Laundry detergentts are
manufactured using proteases (enzyme). (4) Esters used in cosmetics are
manufactured using genetically engineered enzyme.
17➤ Polythene.
=> Ans. It is used in the manufacture of bags, bottles, toys, pipes,
etc.
18➤ Nylon.
=> Ans. It is used in the manufacture of ropes, carpets, tyre cords,
fabrics.
19➤ Orlon
=> Ans. It is used in making blankets as artificial wool.
20➤ Teflon.
=> Ans. It is used in coating for cooking pans, gaskets, valves,
etc.
21➤ PVC.
=> Ans. It is used in the manufacture of sheets, water pipes, hand
bags, etc.
22➤ Melamine
=> Ans. It is used in making crockeries. (15) LDP.
23➤ HDP
=> Ans. (1) HDP is used in manufacture of toys and other household
articles like buckets, dustbins, bottles, pipes, etc. (2) It is used to
prepare laboratory wares and other objects where high tensile strength
and stiffness is required.
24➤ Explain the different applications of nanoparticles.
=> (1) Nanoparticles contribute to stronger, lighter, cleaner and
smarter surfaces and systems. They are used in the manufacture of
scratchproof eyeglasses, transport, sunscreen, crack resistant paints,
etc. (2) Used in electronic devices like Magnetoresistive Random Access
Memory (MRAM). (3) Nanotechnology plays an important role in water
purification techniques. Silver nanoparticles are used in water
purification system to get safe drinking water. (4) Self cleansing
materials : Lotus is an example of self cleansing. Nanostructures on
lotus leaves repel water which carries dirt as it rolls off. Lotus
effect is the basis of self cleaning windows.
2.APPLICATIONS
1➤ What are the uses of semiconductors?
=> Ans. The uses of semiconductors are as follows: (1) They are used
in transistors, digital computers and cameras. (2) They are used in
solar cells and television sets. (3) By combining n-type and p-type
semiconductors, n-p junctions are formed which are effectively used in
rectifiers or to convert light energy into electrical energy.
2➤ Which of the four colligative properties is most often used for molecular mass determination? Why?
=> Ans. (1) Since osmotic pressure has large values, it can be
measured more precisely.. (2) The osmotic pressure can be measured at a
suitable constant temperature. (3) The molecular masses can be measured
more accurately. (4) Therefore, it is more useful to determine molecular
masses of expensive substances by osmotic pressure.
3➤ Explain reverse osmosis. OR How can pure water be obtained from sea water?
=> Ans. Reverse osmosis: The phenomenon of the passage of solvent
like water under high pressure from the concentrated aqueous solution
like sea water into pure water through a semipermeable membrane is
called reverse osmosis. The osmotic pressure of sea water is about 30
atmospheres. Hence, when pressure more than 30 atmospheres is applied on
the solution side, regular osmosis stops and reverse osmosis starts.
Hence pure water from sea water enters the other side of pure water. For
this purpose, suitable semipermeable membrane is required which can
withstand high pressure conditions over a long period. This method is
used successfully in Florida since 1981 producing more than 10 million
litres of pure water per day.
4➤ What are the applications of a buffer solution?
=> (1) In a biochemical system: Blood in our body has pH 7.36-7.42
due to (HCO + H₂CO,) and little change of 0.2 pH unit may be fatal. For
example, saline solution used in intravenous injection contains a buffer
solution maintaining pH of the blood in the required range. (2)
Agriculture: The properties of soil depend upon its pH. The salts
present in soil such as phosphates, carbonates, bicarbonates and organic
acids impart definite pH to the soil. Depending on pH the fertilizers
are selected.. (3) Industry: In many industries, buffer solutions are
used to carry out chemical processes very effectively, such as the
industries of paper, dye, paints, drugs, ink, etc. (4) Medicines : Many
medicines particularly in the liquid state have a good stability and
optimum activity at a definite pH, for which buffer solutions are used.
For example, penciline preparations are carried out in the presence of a
buffer of sodium citrate. A buffer solution of magnesium citrate is
prepared by adding citric acid to Mg(OH)₂. (5) Analytical chemistry: In
a qualitative analysis, the precipitation of groups, the chemical tests
for detection of ions, etc. are carried out at a definite pH. For
example, precipitation of cations of IIIA are carried in the presence of
a basic buffer of pH 8-10 obtained by using NH,OH and NH Cl.
5➤ Explain the application of solubility product in the removal of hardness of water.
=> Ans. The hardness of water is due to presence of Ca²+ ions. It is
surprising to know that Ca²+ ions can be removed by adding more Ca²+
ions in the form of lime Ca(OH),, to the hard water. The OH ions of lime
react with HCO, ions present in the hard water to form CO ions. OH(aq) +
HCO3(aq) →→ CO3(aq) + H₂O(1) Solubility product of CaCO, is very low
(K-4.5 x 10 "). Addition of lime makes IP > >Ksp which results in
the precipitation of CaCO, and thereby removal of hardness.
6➤ What are the applications of Hess's law?
=> Applications: Hess's law is used: (1) To calculate heat of
formation, combustion, neutralisation, ionization, etc. (2) To calculate
the heat of reactions which may not take place normally or directly. (3)
To calculate heats of extremely slow or fast reactions. (4) To calculate
enthalpies of reactants and products.
7➤ What are the applications of Kohlarausch's law?
=> (1) With this law, the molar conductivity of a strong electrolyte
at zero concentration can be determined. For example, (2) A values of
weak electrolyte with those of strong electrolytes can be obtained. For
example, Ao(CH₂COOH) = A(HCI) + Ao(CH,COONa) -^o(NaCl)
8➤ What are the applications of electrolysis?
=> Ans. (1) Refining of metals and electroplating are achieved by
electrolysis. (2) Sea water is the source of 300000 tonnes of Mg
produced every year by electrolysis. (3) Electrochemical art: Al, Cr and
Sn can be coloured by an electrochemical process called anodising. In
this process metal anode oxidises to give metal oxide coat. When an
organic dye is added to the electrolyte, dye molecules soak forming
spongy surface of coating and become trapped with the hardening of the
metal oxide surface.
9➤ What are the applications of electrochemical series (or electromotive series)? (1 mark for each application)
=> Ans. The applications of electrochemical series (or electromotive
series) are as follows: (1) Relative strength of oxidising agents in
terms of Ered values : The Ered value is a measure of the tendency of
the species to be reduced i.e., to accept electrons and act as an
oxidising agent. The species mentioned on left hand side of the half
reactions are oxidising agents. The substances in the upper positions in
the series and hence in the upper left side of the half reactions have
large positive Ered values hence are stronger oxidising agents. For
example, F₂, Ce, Au, etc. As we move down the series, the oxidising
power decreases. Hence from the position of the elements in the
electrochemical series, oxidising agents can be selected. (2) Relative
strength of reducing agents in terms of Ered values: The lower Ered
value means lower tendency to accept electrons but higher tendency to
lose electrons. The tendency for reverse reaction or oxidation increases
as Ered becomes more negative (2) In the manufacture of dyes,
fertilizers like ammonium sulphate, super phosphate, detergents. (3) As
an electrolyte in lead storage battery. (4) As a dehydrating agent. (5)
As an oxidising agent. (6) For refining petroleum. (7) As a pickling
agent for removing layers of basic oxides from the metal surfaces like
Fe, Cu, etc. before the metals are galvanized. electroplated, etc.
10➤ What are the uses of interhalogen compounds?
=> he uses of interhalogen compounds are as follows: (1) ICI is used
as a halogenating agent and also in the estimation of jodine number of
fats and oils. (2) In the preparation of polyhalides, interhalogen
compounds are (3) CIF, and BrF, are widely used as fluorinating agent.
They are used in the separation of isotope by fluorinating (4) In
propellants, CIF, and IF, are used as oxidisers. (5) They are used as
non-aqueous solvents.
11➤ What are the uses of: (1) Helium (2) Neon (3) Argon.
=> Ans. (1) Uses of helium (He): (1) A mixture of helium (85%) and
oxygen (15%) is used for filling. balloons. (ii) A mixture of helium and
oxygen is also used for respiration by sea divers instead of air because
helium is less soluble in blood than nitrogen under high pressure. It is
also used for treatment of asthma. (ii) Helium is used in producing
inert atmosphere in metallurgical operations and welding of metals. (iv)
Liquid helium is used in producing low temperature required (v) Helium
is also used in producing lasers in low temperature gas for research
thermometry. (vi) It is used in magnetic resonance imaging. (2) Uses of
neon (Ne): (1) Neon is used in the production of neon discharge lamps
and signs by filling Ne in glass discharge tubes. (ii) Neon signs are
visible from a long distance and also have high penetrating power in
mist or fog. (1) A mixture of neon and hellum is used in voltage
stabilizers. and current rectifiers. (iv) Neon is also used in the
production of lasers and fluorescent tubes. (3) Uses of argon (Ar): (1)
Argon is used to fill fluorescent tubes and radio valves. (ii) It is
used to provide inert atmosphere for welding and production of steel.
(iii) It is used along with neon in neon sign lamps to obtain. different
colours. (iv) A mixture of 85% Ar and 15% N, is used in electric bulbs
to enhance the life of the filament.
12➤ What are the uses of transition metals?
=> Ans. Transition metals are used as: (A) Catalysts: (1) MnO, is
used as a catalyst in the decomposition of KCIO, 2KCIO, -KC1+30, A (2)
In the manufacture of ammonia by Haber's process, Mo/Fe used as a
catalyst. is Nau+ 2NH (3) In the synthesis of gasoline by Fischer
Tropsch process, Co-Th alloy is used as a catalyst. (4) Finely divided
Ni (formed by reduction of heated oxide in hydrogen) is very efficient
catalyst in hydrogenation of ethene to ethane at 140 °C. A HC CHH-H NI
10 CHC-CH₂ HỌC.CH, Ethene Ethane (B) In the formation of alloys: (1) The
transition metals form a large number of alloys among themselves, which
are hard with high melting points. (2) During alloy formation atoms of
one metal are distributed randomly in the lattice of another metal. (3)
The metals with similar atomic radii and similar properties readily form
alloys. (4) These alloys have industrial importance. (5) The alloys can
be ferrous alloys or nonferrous alloys.
13➤ What are the application of lanthanoids?
=> Ans. (1) Lanthanoid compounds are used in the colour television
tubes and computer monitor. For example, mixed oxide (Eu. Y),0, 1
releases an intense red colour when bombarded with high energy
electrons. (2) Lanthanoid lons are used as active lons in luminescent
materials. (Optoelectronic application) (3) Nd YAG laser is the most
notable application. (Nd YAG neodymium doped ytterium aluminium garnet)
(4) Erbium doped fibre amplifiers are used optical fibre commu nication
systems. (5) Lanthanoids are used in cars, superconductors and permanent
magnets.
14➤ What are the applications of actinoids?
=> Ans. (1) Thorium oxide (ThO,) with 1% CeO, is used as a major
source of indoor lighting, as well as for outdoor camping. (2) Uranium
used in the nuclear reactors. (3) The isotopes of Thorium and Uranium
have very long half-life, so that we get very negligible radiation from
them: Hence they can be used safely.
