PAGE NO : 247
Solution 1:
Solution 2:
Solution 3:
Solution 4:
Solution 5:
Solution 6:
Solution 7:
Solution 8:
Solution 9:
Solution 10:
Solution 11:
Solution 12:
Solution 13:
Solution 14:
Solution 15:
Solution 16:
Solution 17:
PAGE NO : 229
Solution 1:
Solution 2:
Solution 3:
Solution 4:
PAGE NO : 230
Solution 5:
Solution 6:
Solution 7:
Solution 8:
Solution 9:
Solution 10:
Solution 11:
PAGE NO : 231
Solution 1993-1:
Solution 1994-1:
Solution 1994-2:
Solution 1994-3:
Solution 1995-4:
Solution 1995-5:
Solution 1995-1:
Solution 1995-2:
Solution 1995-3:
Solution 1996-1:
Solution 1998-1:
Solution 1998-2:
Solution 1998-3:
PAGE NO : 232
Solution 1999-1:
Solution 1999-2:
Solution 2000-1:
Solution 2002-1:
Solution 2003-1:
Solution 2003-2:
Solution 2003-3:
PAGE NO : 233
Solution 2004-1:
Solution 2005-3:
Solution 2005-2:
Solution 2006-1:
Solution 2007-1:
Solution 2007-2:
Solution 2007-3:
PAGE NO : 234
Solution 2008-1:
Solution 2008-2:
Solution 2009-1:
PAGE NO : 216
Solution 1:
Solution 2:
Solution 3:
PAGE NO : 217
Solution 4:
Solution 5:
Solution 6:
Solution 7:
Solution 8:
Solution 9:
Solution 10:
Solution 11:
Solution 12:
Solution 13:
Solution 14:
Solution 15:
Solution 16:
Solution 17:
PAGE NO : 218
Solution 18:
Solution 19:
Solution 1991-1:
Solution 1991-2:
Solution 1991-3:
Solution 1992-1:
Solution 1992-2:
Solution 1992-3:
Solution 1992-4:
Solution 1994-1:
Solution1994-2:
Solution 1994-3:
Solution 1994-4:
Solution 1995-1:
Solution 1997-1:
PAGE NO : 219
Solution 1998-1:
Solution 1999-1:
When concentrated nitric acid is added to copper brown fumes of nitrogen dioxide are observed.
Solution 2000-1:
Solution 2001-1:
Solution 2001-2:
Solution 2001-3:
Solution 2002-1:
Solution 2002-2:
Solution 2002-3:
Solution 2002-4:
Platinum glaze is used as catalyst in the manufacture for nitric acid
Solution 2003-1:
Solution 2003-2:
Solution 2005-1:
Solution 2005-2:
Solution 2006-1:
Solution 2007-1:
Solution 2007-2:
Solution 2008-1:
Solution 2008-2:
<
Solution 2009-1:
PAGE NO : 204
Solution 1:
Ammonia is found both in free state and in combined state. In free state, it is formed in traces amount by decaying urine and other organic matter.
In combined state, ammonia is found as ammonium salts mainly as ammonium chloride and ammonium sulphate.
Solution 2:
Solution 3:
Solution 4:
Solution 5:
Solution 6:
Solution 7:
PAGE NO : 205
Solution 8:
Solution 9:
Solution 10:
Solution 11:
Solution 12:
Solution 13:
Solution 14:
Solution 15:
Solution 16:
Solution 17:
PAGE NO : 206
Solution 18:
Solution 19:
Solution 20:
Solution 21:
Solution 22:
Solution 1992-1:
Silver chloride
Solution 1992-2:
Ammonia is highly soluble gas in water and so cannot be collected over water.
Solution 1992-3:
Ammonia is the odd one out.
Ammonia forms weakly basic solution when dissolved in water.
The others give acidic solution when dissolved in water.
Solution 1992-4:
Solution 1992-5:
Solution 1993-1:
Solution 1993-2:
Solution 1994-1:
Solution 1994-2:
Solution 1994-3:
PAGE NO : 207
Solution 1995-1:
The cation is Cu2+ ion. Solution B is copper sulphate. It is bright blue in colour.
Solution 1995-2:
Three ways to identify ammonia gas:
Solution1995-3:
Solution 1995-4:
This reaction shows that ammonia is a reducing agent.
Solution 1995-5:
This process is called as Ostwald’s Process .The catalyst used is platinum.
Solution 1995-6:
During laboratory preparation of ammonia, it is passed through a drying tower containing quicklime (calcium oxide).
Ammonia is collected in an inverted dry gas jar by the downward displacement of air.
Solution 1995-7:
Ammonia gas
Solution 1996-1:
Ammonia forms ammonium hydroxide and turns red litmus blue as it is alkaline in nature.
Solution 1996-2:
Solution 1996-3:
Haber’s process is used in industrial preparation of ammonia.
Gaseous inputs in Haber’s process are dry nitrogen and dry hydrogen gas. They are mixed in the ratio of 1:3 by volume.
The following conditions favour maximum yield of ammonia:
The gases after reaction pass through condensing pipes of cooling chamber where ammonia gets liquefied and is collected in receiver.
Ammonia can also be collected by downward displacement of air.
Solution 1997-1:
Solution 1997-2:
Solution 1998-2:
Ammonium salts are used as fertilizers in fields.
Solution 1998-3:
Solution 1998-1:
Dry ammonia are neutral to litmus. An aqueous solution of ammonia turns red litmus blue stating that it is basic in nature.
PAGE NO : 208
Solution 1998-4:
Solution 1998-5:
Solution 1991-1:
Solution 2001-1:
Ammonia
Solution 2001-2:
Solution2001-3:
Solution 2001-4:
Aqueous solution is acidic in nature due to presence of hydrogen ion.
Aqueous solution of ammonia is weakly basic in nature due to presence of hydroxyl ion.
Solution 2002-2:
Thermal dissociation.
Solution 2002-1:
Solution 2003-1:
Solution 2003-2:
Ammonia is collected by downward displacement of air.
Solution 2003-3:
Ammonia is highly soluble in water and so it is not collected over water.
Solution 2003-4:
Quick lime (calcium oxide) is used as a drying agent for ammonia.
Solution 2004-1:
Solution 2004-4:
Solution 2005-1:
PAGE NO : 209
Solution 2005-2:
Solution 2006-1:
Solution 2006-2:
Solution 2007-1:
By the pungent smell of ammonia gas.
Solution 2007-2:
Solution 2008-1:
(c) Magnesium nitride
PAGE NO : 185
Solution 1:
PAGE NO : 186
Solution 2:
Solution 3:
Solution 4:
Solution 5:
Solution 6:
Solution 7:
Solution 8:
PAGE NO : 187
Solution 9:
Solution 10:
Solution 11:
Solution 12:
Solution 13:
Solution 14:
Solution 15:
Solution 1991-1:
Solution 1992-1:
PAGE NO : 188
Solution 1992-2:
Solution 1992-3:
Solution 1994-1:
Solution 1995-1:
Solution 1996-1:
Solution 1997-1:
Solution 1998-1:
Solution 2000-1:
Solution 2000-2:
Solution 2000-3:
Solution 2000-4:
PAGE NO : 189
Solution 2001-1:
Solution 2001-2:
Solution 2001-3:
Solution 2002-1:
Solution 2002-2:
Solution 2004-1:
Solution 2004-2:
Solution 2004-3:
Solution 2005-1:
Solution 2005-2:
Solution 2006-1:
Solution 2007-1:
Solution 2008-1:
Solution 2009-1:
Solution 2009-2:
PAGE NO :170
Solution 1:
On heating certain solids they don’t melt and directly get converted to their gaseous form, this process of direct conversion of solids to their gaseous form is called as sublimation. For ex: camphor and ammonium chloride undergo sublimation.
Solution 2:
Decrepitation is a process of breaking up of solid particles on heating, which makes a crackling sound. Lead nitrate decrepitate on heating.
Lead nitrate
Solution 3:
(a) Zn(NO)3 = white
(b) Cu(NO3)2 = blue
(c) CuSO4.5H2O = blue
(d) CuSO4 = pale green
(e) K2Cr2O7 = orange
(f) PbS = black
Solution 4:
Solution 5:
Solution 6:
Solution 7:
Solution 8:
(a) Rotten egg
(b) Burning sulphur
(c) Nitrogen dioxide
(d) Alkali
(e) Ca(OH)2
(f) Lilac
(g) Brick-red
Solution 9:
Point sources of water pollution: Sources of water pollution that discharge directly into the water source are called as point sources of water pollution.
For ex: factories
Non point sources of water pollution: sources of water pollution that remain scattered and don’t have specific locations for the discharge of pollutants into particular water bodies are called as non point sources of water pollution.
For ex: run off from fields.
Solution 10:
PAGE NO :158
Solution 1:
Acid rain is the rain that has an excessive amount of acid in it than that of normal. Two air pollutants that cause acid rain are-
Solution 2:
Acid rain is responsible for retarding forest’s growth and other vegetation. Acid rain makes the soil acidic and adversely affects the plants.
Solution 3:
70% of acid rain is due to sulphur dioxide. Oxides of sulphur and nitrogen released into atmosphere from number of sources.These oxides of nitrogen gets converted into nitrogen dioxide(NO2) which reacts with water to form nitric acid.Similarly, sulphur dioxide reacts with atmospheric oxygen to form sulphur trioxide which with water forms sulphuric acid.These come down on earth as acid rain.
Solution 4:
Acid rain can be reducd by-
Solution 5:
Acid rain cause extensive damage to the environment.
Solution 6:
Air pollution is a harmful change in the natural air quality. It includes all physical, chemical and biological agents that modify the natural characteristics of the atmosphere.
Solution 7:
Ozone is an allotrope of oxygen. It has three oxygen atoms and its molecular formula is O3.It is an unstable blue gas having pungent odour found in troposphere. It is used as a powerful oxidant, bleach and water purifier.
Solution 8:
The gases causing ozone depletion are-
Solution 9:
Greenhouse gases are-
Solution 10:
Solution 11:
Greenhouse effect means the progressive warming up of the earth’s surface due to the blanketing effect of man made carbon dioxide in the atmosphere. Greenhouse is a glasshouse with plants inside and which allows short wave, incoming solar radiation to come in but does not allow the long wave,i.e. outgoing infrared radiation to escape from inside the structure. Some of the gases in the earth’s atmosphere act like the glass in a greenhouse.They trap sun’s heat and keep the surface of the earth warm. Carbon dioxide and water vapour act as a greenhouse.
Solution 12:
Global warming is rise in the average global earth temperature . An increase in the average temperature of the earth’s atmosphere due to greenhouse effect which can have far reaching effects on the climate and consequently on the key life, support systems of the planet, and this phenomenon is called global warming.
Solution 13:
f
Solution 14:
Solution 15:
It has been found that in every southern spring(September-October) 50-95 % of stratospheric ozone is destroyed at a height of 15-24 kms above ‘Antarctica’ creating pockets which have been described as ozone hole.
Solution 16:
The adverse effects of ozone layer depletion are-
Solution 17:
Natural greenhouse effect is a process of thermal blanketing of the earth which maintains its temperature to sustain life on it. Without greenhouse effect, the climate of the earth would be too cold for most of the life to survive.
Solution 18:
The effect of warming and insulation of the earth caused due to some heat trapping gases accumulated in the atmosphere after their emission from the earth surface is called as greenhouse effect. Due to this there is rise in the average global earth temperature called global warming.
Solution 19:
When an ozone molecule is hit by UV wavelengths, it absorbs the radiant energy and photo dissociates into O2 and O giving off heat. Thus, keeps the UV radiation from reaching the earth’s surface and also causes a temperature inversion in the stratosphere that helps to maintain relatively stable climatic conditions on and near the ground.
Solution 20:
When an ozone molecule is hit by UV wavelengths, it absorbs the radiant energy and photo dissociates into O2 and O giving off heat. Thus, keeps the UV radiation from reaching the earth’s surface and also causes a temperature inversion in the stratosphere that helps to maintain relatively stable climatic conditions on and near the ground.
PAGE NO : 152
Solution 9:
Solution 10:
Solution 11:
Solution 12:
Solution 13:
PAGE NO : 169
Solution 1:
Solution 2:
Solution 3:
PAGE NO : 170
Solution 4:
Solution 5:
Solution 6:
As we know that minerals are the naturally occurring compounds of metals which are generally mixed with earthy such as soil, sand, limestone and rocks while ores are those minerals from which a metal can be extracted profitably.
Hence “All ores are minerals but all minerals are not ores”.
Solution 7:
Solution 8:
Solution 9:
Refining of metals: It is the further purification of metals obtained by reduction process to remove all the impurities.
Depending upon the nature of metal, nature of impurities and purpose for which metal is to be used. The three methods used for refining are:
Solution 10:
Solution 11:
Solution 12:
Solution 13:
Cryolite acts as a solvent for the electrolytic mixture in the electrolytic reduction of alumina in the Hall’s process.
Solution 14:
Solution 15:
Solution 16:
An alloy is a homogeneous mixture of two or more metals fused together and then solidified.
Alloys are made because they have many salient features:
Solution 17:
The properties of alloys which are different from constituent metals are:
Solution 18:
Amalgam: A mixture or an alloy of mercury with a number of metals or non-metals is known as amalgams. An amalgam may be liquid such as Na/Hg or a solid like Zn/Hg.
Solution 19:
Solution 20:
Solution 21:
PAGE NO : 171
Solution 1991-1:
Solution 1991-2:
Zinc amalgam which is a mixture of zinc and mercury.
Solution 1992-1:
Solution 1992-3:
Solution 1992-:
Solution 1993-1:
Gold.
Solution 1993-2:
Solution 1994-1:
Reactivity of metals with water Sodium, calcium, magnesium, iron
Solution 1994-2:
Solution 1995-1:
Solution 1995-2:
Zinc amalgam.
PAGE NO : 172
Solution 1996-1:
Solution 1996-2:
Solution 1996-3:
An alloy is a homogeneous mixture of two or more metals fused together and then solidified.
Solution 1997-1:
Chromium and nickel is added to steel to make it stainless steel.
Solution 1997-2:
Ore: Those minerals from which a metal can be extracted profitably are called ores. For example bauxite ore is used to extract aluminium metal, hematite ore is used to extract iron metal.
Solution 1998-1:
Solution 1998-2:
Solution 1998-3:
Metals have 1, 2, 3 valence electrons while non-metals have 4, 5, 6 or 7 valence electrons.
Solution 1999-1:
Magnesium oxide, iron (II) oxide, lead (II) oxide and then copper (II) oxide.
Solution 1999-2:
Solution 1999-3:
PAGE NO : 173
Solution 2000-1:
Solution 2001-1:
Solution 2001-2:
Sodium > magnesium > Zinc > Iron > Copper
Solution 2002-1:
Solution 2002-2:
Solution 2003-1:
Solution 2004-1:
Iodine is a non- metal that has a metallic luster and sublimes on heating.
Solution 2004-2:
Solution 2004-3:
Zinc blende (ZnS)
Solution 2004-4:
Solution 2004-5:
Galvanization.
Solution 2004-6:
Solution 2005-1:
PAGE NO : 175
Solution 2005-2:
Solution 2006-1:
Solution 2007-1:
Solution 2008-1:
(b)
PAGE NO : 176
Solution 2009-1:
Solution 2009-2:
Solution 2009-3:
Solution 2009-4:
Ex No: 25.1
Solution 1.
Solution 2.
Solution 3.
Solution 4.
Solution 5.
Volume of a cuboid = l x b x h
2400 = 20 × 15 × h
h = 8 cm
Hence, height of the cuboid is 8 cm.
Solution 6.
Solution 7.
Solution 8.
Solution 10.
Solution 11.
Solution 12.
Solution 13.
Solution 14.
Solution 15.
Solution 16.
Solution 17.
Solution 21.
Solution 22.
Solution 23.
Solution 24.
Solution 26.
Solution 27.
Solution 28.
Solution 30
Solution 32.
Solution 33.
Solution 34.
Solution 35.
Solution 36.
Solution 39.
Ex No: 25.2
Solution 1.
Solution 2.
Solution 3.
Solution 4.
Solution 5.
Solution 6.
Solution 7.
Solution 9.
Solution 10.
Solution 11.
Solution 12.
Solution 13.
Solution 15.
Solution 16.
Solution 17.
Solution 18.
Solution 19.
Solution 20.
Solution 21.
Solution 23.
Solution 25.
Solution 26.
Solution 27.
Solution 28.
Solution 29.
Solution 30.
Solution 31.
Ex No: 25.3
Solution 1.
Solution 2.
Solution 3.
Solution 4.
Solution 5.
Solution 6.
Solution 7.
Solution 8.
Solution 9.
Solution 10.
Solution 11.
Solution 12.
Solution 13.
Solution 14.
Solution 15.
Ex No: 15.2
Solution 1:
Solution 2:
Solution 3:
Solution 4:
Solution 5:
Solution 6:
Note: This question is incomplete.
According to the information given in the question,
F could be any point on BC as shown below:
So, this makes it impossible to prove that DP = DE, since P too would shift as F shift because P too would be any point on DE as F is.
Note: If we are given F to be the mid-point of BC, the result can be proved.
Solution 7:
From the figure EF ∥ AB and E is the midpoint of BC.
Therefore, F is the midpoint of AC.
Here EF ∥ BD, EF = BD as D is the midpoint of AB.
BE ∥ DF, BE = DF as E is the midpoint of BC.
Therefore BEFD is a parallelogram.
Remark: Figure modified
Solution 8:
Solution 9:
Ex No: 20.1
Solution 1:
Solution 2:
Solution 3:
Solution 4:
Solution 5:
Solution 6:
Solution 7:
Solution 8:
Solution 9:
Solution 10:
Solution 11:
Solution 12:
Solution 13:
Solution 14(a):
Steps of construction:
Draw AD = 3.2 cm
Draw ∠XAD = 90°.
With D as centre and radius BD = 5.5 cm, draw an arc to cut AX at point B.
Join BD.
With B as centre and radius 3.2 cm draw an arc and with D as centre and radius = AB, draw another arc to cut the previous arc at C.
Join BC and CD.
Thus, ABCD is the required rectangle.
CD = 4.5 cm
Solution 14(b):
Steps of construction:
Draw BC = 6.2 cm
Through B, draw BP such that ∠B = 90°
From BP, cut BA = 5 cm
With A and C as centres and radii 6.2 cm and 5 cm respectively, draw arcs cutting each other at D.
Join AD and CD.
Thus, ABCD is the required triangle.
Solution 15:
Solution 16:
Solution 17:
Solution 18(a):
Since area of rectangle = 21 cm2
And, length = 4.2 cm
Breadth = Area ÷ Length = 21 ÷ 4.2 = 5 cm
Steps of construction:
Draw BC = 5 cm
Through B, draw BP such that ∠B = 90°
From BP, cut BA = 4.2 cm
With A and C as centres and radii 5 cm and 4.2 cm respectively, draw arcs cutting each other at D.
Join AD and CD.
Thus, ABCD is the required triangle.
Solution 18(b):
Since area of rectangle = 33.8 cm2
And, breadth = 6.5 cm
Length = Area ÷ Breadth = 33.8 ÷ 6.5 = 5.2 cm
Steps of construction:
Draw BC = 6.5 cm
Through B, draw BP such that ∠B = 90°
From BP, cut BA = 5.2 cm
With A and C as centres and radii 6.5 cm and 5.2 cm respectively, draw arcs cutting each other at D.
Join AD and CD.
Thus, ABCD is the required triangle.
Solution 19:
Solution 20:
