a) For domestic wastes- we can have a compost pit. As vegetable waste is dumped in the pit, they rot and become manure.
b) Metallic can - method - Recycle
c) Yes, this disposal method protects the environment because recycling saves energy. It also reduce green house gas emissions which helps to tackle climate change.

Deforestation gives rise to ecological problems like floods, drought, soil erosion, loss of wild life, extinction of species, imbalance of biogeochemical cycles, alternation of climatic conditions and desertification.

(i) Overcome the rapid depletion of ground water levels.
(ii) To meet the increase demand of water.
(iii) Reduce flood and soil erosion.
(iv) Used for drinking purpose.

Parental generation:
i) Pure breeding tall plant and a pure breeding dwarf plant (tt).
F₁ generation:
i)  Plants raised from the seeds of pure breeding parental cross in F₁ generation were tall and monohybrids.
F₂ generation:
i) Selfing of the F₁ monohybrids resulted in tall and dwarf plants respectively in the ratio of 3:1.
ii) The actual number of tall and dwarf plants obtained by Mendel was 787 tall and 277 dwarf.
iii) External expression of a particular trait is known as phenotype. So the phenotypic ratio is 3:1.
In the F₂ generation 3 different types were obtained:
i) Tall Homozygous - TT (Pure) - 1.
ii) Tall Heterozygous - Tt - 2.
iii) Dwarf Homozygous - tt -1.
So the genotypic ratio 1:2:1.
(A genotype is the genetic expression of an organism).

(i) Allosomes are chromosomes which are responsible for determining the sex of an individual.
(ii) They are also called as sex chromosomes or hetero-chromosomes.
 

(i) Pea plant is naturally self-pollinating and so is very easy to raise pure breeding individuals.
(ii) It has a short life span as it is an annual and so it was possible to follow several generations.
(iii) It is easy to cross-pollinate.
(iv) It has deeply defined contrasting characters.
(v) The flowers are bisexual.

1. Click events in script option

3. Click Looks in script option. Drag “say” to script area.

4. Type “Hello “ word in say tab.

5.Click sounds in script option. Drag play sound to script area. Choose the hello sound from the audio file.

6. From File menu choose the Save option.
7. Click the green flag at the top right corner of the stage window to run the program

i) Thyroid hormone is essential for normal physical, mental and personality development.
ii) Hence it is called as the personality hormone.

Application of auxin on plants will prevent leaf fall and fruit drop in plants because Auxins prevent the formation of abscission layer.

(i) Bolting is production of a flowering stem in plants.
(ii) Treatment of rosette plants with gibberellin induces sudden shoot elongation followed by flowering. This is called bolting.

(i) Sometimes cells, tissues and organs in the body may be permanently damaged or lost due to genetic to disease or injury.
(ii) In such situations stem cells are used for the treatment of diseases which is called stem-cell therapy.

Protina, shakti and Rathna are lysine rich maize hybrids.

Crop	Variety	Resistance to diseases
Wheat	Himgiri	Leaf and stipe rust, hill bunt
Cauliflower	Pusa Shubhra, Pusa Snowball K-1	Black rot
Cowpea	Pusa Komal	Bacterial blight

(a) Pollination:
The transfer of pollen grains from anther to stigma of a flower is called as pollination.
Types of pollination :
(i) Self-pollination
(ii) Cross pollination
Self-pollination (Autogamy)
(i) Self pollination is also known as autogamy.
(ii) The transfer of pollen grain from the anther to the stigma of same flower or another flower borne on the same plant is known as self pollination. e.g.Hibiscus.
(b) Advantages of self-pollination:
(i) Self-pollination is possible in certain bisexual flowers.
(ii) Flowers do not depend on agents for pollination.
(iii) There are no wastages of pollen grains.
Disadvantages of self-pollination:
(i) The seeds are less in number.
(ii) The endosperm is minute. Therefore, the seeds produce weak plants.
(iii) New varieties of plants cannot be produced.

A - Exine
B - Intine
C - Generative cell
D - Vegetative nucleus

Maintaining menstrual hygiene is important for the overall health of women.
The basic menstrual hygiene ways are:
(i) Sanitary pads should be changed regularly, to avoid infections due to microbes from vagina and sweat from genitals.
(ii) Use of warm water to clean genitals helps to get rid of menstrual cramps.
(iii) Wearing loose clothing rather than tight fitting clothes will ensure the airflow around the genitals and prevent sweating.

S.No	Medullated nerve fibre	Non-medullated nerve fibre
i)	Medullated Nerve fibre is also known as myelinated or white neuron. Because axon is covered with myelin sheath.	Non-Medullated Nerve fibre is also known as non-myelinated or grey neuron Because axon is not covered myelin sheath.
ii)	Myelin sheath is produced by a layer of Schwann cells or neurilemma.	Schwann cells are absent.
iii)	Node of Ranvier is present.	Node of Ranvier is absent.
iv)	They conduct impulse at a faster speed.	Conduct impulses slower than medullated fibres.
v)	These are present in the white matter of brain, spinal cord and in cranial and spinal nerves.	These are present in autonomic nerves and axons within the CNS as Grey matter.

S.No	Voluntary actions	Involuntary actions
i)	An action which is under conscious control.	An action which is not under conscious control.
ii)	Voluntary action is controlled by the brain.	Involuntary action is controlled by the spinal cord.
iii)	All voluntary actions result in a muscular action.	Involuntary actions result in a muscular action (or) secretion from some gland.

Systemic circulation	Pulmonary circulation
Systemic circulation  moves blood between the heart and the rest of the body.	Pulmonary circulation moves blood  between the heart and the lungs.
It sends oxygenated blood out to cells and returns deoxygenated blood to the heart.	It transports deoxygenated blood to the lungs to absorb oxygen and release carbon dioxide. The oxygenated blood then flows back to the heart.

 

(i) Transpiration often results in water deficit which causes injury to the plants by desiccation.
(ii) Excessive rate of transpiration leads to stunted growth of plants.

The force of attraction between molecules of water is called cohesion.

(i) The age of fossils is determined by radioactive elements present in it.
(ii) They may be carbon, uranium, lead or potassium.
(iii) It is used in paleobotany and anthropology for determining the age of human fossils and manuscripts.

(i) Ethnobotany is the study of a region's plants and their practical uses through the traditional knowledge of the local culture of people.
Importance of Ethnobotany :
(i) It provides traditional uses of plant.
(ii) It gives information about certain unknown and known useful plants.
(iii) The ethnomedicinal data will serve as a useful source of information for the chemists, pharmacologists and practitioners of herbal medicine.
(iv) Tribal communities utilize ethnomedicinal plant and prepare medicine to cure many  diseases.

(i) Archaeopteryx is considered to be a connecting link between reptiles and birds.
(ii) It had wings with feathers like a bird. It has long tail, clawed digits and conical teeth like a reptile.

(i) For diabetic patients, the food to be avoided are:
a. Refined sugars (sucrose and glucose).
b. Saturated fat intake should be reduced.
These food release sugars rapidly in the blood stream.
(ii) The food to be included in diabetic patients are:
a. Flax seeds containing insoluble fiber, Guavas, Tomatoes and Spinach.
b. Diet comprising whole grains, millets (jowar, bajra, ragi), green leafy vegetables, wheat and unpolished rice should be included in diet regularly. These foods help reduce blood sugar levels.

(i) Cancer is an abnormal and uncontrolled division of cells that invade and destroy surrounding tissues forming a tumor neoplasm (new growth).
(ii) It is a heterogenous group of cells that do not respond to the normal cell division.
(iii) The cancerous cells migrate to distant parts of the body and affect new tissues.

HIV is transmitted generally by
(i) Sexual contact with infected person.
(ii) Use of contaminated needles or syringes especially in case of intravenous drug abusers.
(iii) By transfusion of contaminated/infected blood or blood products.
(iv) From infected mother to her child through the placenta.

Rings of cartilages are found in the tracheal walls of rabbit to help in the free passage of air.

Carbon dioxide + Water ➝ Glucose + Water + Oxygen

(i) Photosynthesis is a process by which autotrophic organisms like green plants, algal and chlorophyll containing bacteria utilize the energy from sunlight using CO₂ and H₂O to synthesize their own food.
(ii) It occurs in the chloroplasts of the cell.
\(6 \mathrm{CO}_2+12 \mathrm{H}_2 \mathrm{O} \underset{\text { Chlorophyll }}{\stackrel{\text { Light }}{\longrightarrow}} \mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6+6 \mathrm{H}_2 \mathrm{O}+6 \mathrm{O}_2 \uparrow\)

The three basic tissue systems is flowering plants are
(i) Dermal or Epidermal tissue system
(ii) Ground tissue system
(iii) Vascular tissue system

(i) To increase the productivity of crops
(ii) Remains fresh beyond their normal life time

(i) The nuclear bomb dropped during World War II emitted gamma radiation.
(ii) Gamma rays caused injury to genes in the reproductive cells.
(iii) This gives rise to mutations which pass on from generation to generation.

When an alpha particle emitted atomic number decreases by two, mass number decreases by four. Now three alpha particles are emitted, atomic number decreases by six, the mass number decreases by twelve,
\({ }_{88} \mathrm{Ra}^{226} \longrightarrow{ }_{82} \mathrm{X}^{214}+3{ }_{2} \mathrm{He}^{4}\) 
A = 214,   Z = 82
Number of neutrons in the daughter element N = A - Z 
N = 214 - 82
N = 132

d = 680 m
t = 1.1 + 0.9 = 2, c = ?
\(d=\frac { ct }{2} \)
c = \(\frac { 2 \times d }{ t } \)
\(c=\frac { 2\times 680 }{ 2 } \)
c = 340 ms^-1 which is the speed of sound in air

S.No	Resistivity	Conductivity
(i)	It is the resistance of a conductor of unit length and unit area of cross section.	The reciprocal of electrical resistivity of a material is called electrical conductivity.
(ii)	Its unit is ohm meter	Its unit is ohm-1 meter-1
(iii)	Resistivity is less for conductor than for insulators	Conductivity is more for conductors than for insulators.
(iv)	ρ = RA / L	σ = 1 / ρ

According to Ohm's law, at a constant temperature, the steady current 'I' flowing through a conductor is directly proportional to the potential difference 'V' between the two ends of the conductor.
\(I\alpha V \Rightarrow\)  V = IR

Electric potential : The electric potential at a point is defined as the amount of work done in moving a unit positive charge from infinity to that point against the electric force.
Electric potential difference : The electric potential difference between two points is defined as the amount of work done in moving a unit positive charge from one point to another point against the electric force.

In the cases given below there will be no Doppler effect.
(i) When source (S) and listener (L) both are at rest.
(ii) When source (S) and listener (L) are moving in mutually perpendicular directions.
(iii) When source (S) and listener (L) move in such a way that distance between them remains constant.
(iv) If the source (S) is situated at the center of the circle along which the listener (L) is moving.

Given
\(\mathrm{t}=46^{\circ} \mathrm{C} \)
\(\mathrm{V}_{0}=331 \mathrm{~ms}^{-1} \)
\(\mathrm{V}_{\mathrm{T}}= ? \)
\(\mathbf{V}_{\mathbf{T}}=\left[\mathrm{V}_{0}+\mathbf{0 . 6 1} \mathrm{T}\right] \)
\(=331+[0.61 \times 46]\)
= 331 + [28.06]
= 359.06 ms^-1
The velocity of sound in air at 46^oC is 359.06 ms^-1

\(\text { Molar mass of } \mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}=\mathrm{Al} \times 2+3[\mathrm{~S} \times 1+\mathrm{O} \times 4]\)
\(27 \times 2+3[32 \times 1+16 \times 4]\)
= 54 + 3[32 + 64]
= 54 + 3 [96]
Molar Mass = 54 + 288 = 342
\(\text { Mass } \% \text { of an element }=\frac{\text { mass of that element in the compound }}{\text { molar mass of the compound }} \times100\)
\(\text { Mass } \% \text { oxygen in } \mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}=\frac{192}{342} \times 100 \)
\(=0.5614 \times 100=56.14 \% \)
\(\text { Mass } \% \text { of oxygen in } \mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3} \text { is } 56.14 \%\)

Change in volume \((\Delta V)=0.3-0.25 =0.05\mathrm{~m}^{3}\)
Original volume \(\left(V_{0}\right)=0.3 \mathrm{~m}^{3}\)
Change in Temperature \(\Delta \mathrm{T}=50 \mathrm{~K}\)
\(a_{\mathrm{V}} =?  \)
\(\frac{\Delta V}{V_{0}} =a_{\mathrm{V}} \Delta \mathrm{T}\)
\(a_{\mathrm{V}} =\frac{0.05}{0.3 \times 50}=\frac{0.05}{15}=0.0033 \mathrm{~K}^{-1}\)
Co-efficient of cubical expansion of Zinc bar 0.0033

Area of copper rod,   A_o = 10 m²
Changes of Area of cross section,
Initial temperature \(\Delta \mathrm{A} =11 -10 =1 \mathrm{~m}^{2}  \)
\(\mathrm{~T}_{1} =90 \mathrm{~K}  \)
\(a_{\mathrm{A}} =0.0021 / \mathrm{K}  \)
\(\mathrm{T}_{2} =?  \)
\(\frac{\Delta A}{A_{0}} =a_{\mathrm{A}} \Delta \mathrm{T}  \)
\(\frac{1 }{10 } =0.0021\left[\mathrm{~T}_{2}-90\right]  \)
\(0.1 =0.0021\left[\mathrm{~T}_{2}-90\right]=\frac{0.1}{0.0021}+90=\mathrm{T}_{2}  \)
\(\mathrm{~T}_{2} =137.61 \mathrm{~K}\)
So the final temperature of a copper rod is 137.61 K

\(\text { Given } \quad \mathrm{F}_{1} =140 \mathrm{~N}  \)
\(\mathrm{~d}_{1} =40 \mathrm{~cm}=40 \times 10^{-2} \mathrm{~m}  \)
\(\mathrm{~F}_{2} =40 \mathrm{~N}  \)
\(\mathrm{~d}_{2} =?\)
The moment of force on the nut,
\(=F_{1} \times d_{1}=140 \times 40 \times 10^{-2}  \)
\(=56 \ \mathrm{Nm}\)
The same moment of force is required to unscrew the nut,
\(\mathrm{F}_{2} \times \mathrm{~d}_{2}  =40 \times d_2\)
In both cases, moment of forces applied are equal,
F₁ x d₁ = F₂ x d₂
56 = F₂d₂
\(56=40 \times \mathrm{d}_{2}  \)
\(\mathrm{~d}_{2}=\frac{56}{40}=1.4 \mathrm{~m}  \)
\(\mathrm{~d}_{2}=1.4 \mathrm{~m}\)
The spanner with the longer handle requires very less force to unscrew the same nut.

Given \(\mathrm{m}=1 \mathrm{~kg}, \quad \mathrm{v}=10 \mathrm{~m} \mathrm{~s}^{-1}\)
When a ball bounces back with the same speed, the momentum changes from mv to -mv. So, the change in momentum is -2 mv.
Δp = mv - mu
= -mv - mv
\(=-2 \mathrm{mv}=-2 \times 1 \times 10 \)      \([Here \ mu = mv \\ mv = -mv]\)
\(\therefore \Delta P=-20 \mathrm{~kg} \mathrm{~m} \mathrm{~s}^{-1}\)

\(\text {Given } m_{1} : m_{2}=3: 4  \)          
\(a_{2} =12 \mathrm{~m} \mathrm{~s}^{-2}  \)
\(a_{1} =?\)
Using Newton's second law,
\(\mathrm{F} =\mathrm{m \times a}  \)
\(\mathrm{F} =\mathrm{m}_{1} \times a_{1}=3 a_{1}  \)
\(\mathrm{~F} =\mathrm{m}_{2} \times a_{2}=4 \times 12=48 \mathrm{~N}  \)
\(3 a_{1} =48  \)
\(a_{1} =48 / 3=16 \mathrm{~m} \mathrm{~s}^{-2}  \)
\(a_{1} =16 \mathrm{~ms}^{-2}\)
The acceleration produced on the other body is \(16 \mathrm{~m} \mathrm{~s}^{-2}\).

Deliquescence substances	Hygroscopic substances
When exposed to the atmosphere at ordinary temperature, they absorb moisture and do not dissolve.	When exposed to the atmospheric air at ordinary temperature, they absorb moisture and dissolve.
Hygroscopic substances do not change its physical state on exposure to air.	Deliquescent substances change its physical state on exposure to air.
Hygroscopic substances may be amorphous solids or liquids.	Deliquescent substances are crystalline solids.
Hygroscopic substances are used as drying agents.	Deliquescent Substances are not used as drying agent.
Example : H2SO4.P2O5	Example : NaOH, KOH

a) MgSO₄.7H₂O is heating process:
(i) Magnesium Sulphate heptahydrate or Epsom salt MgSO₄.7H₂O water of crystallization is 7.
(ii) When magnesium sulphate heptahydrate crystals are gently heated, it loses seven water molecules, and becomes anhydrous magnesium sulphate.

(iii) If you add few drops of water or allow it to cool, the colourless anhydrous salt again turns back into hydrated salt.
b) Solubility:
b) Solubility is defined as the number of grams of a solute that can be dissolved in 100g of a solvent to form its saturated solution at a given temperature and pressure.
Solubility = \(\frac{Mass \ of \ the \ solute}{Mass \ of \ the \ solvent}\) x 100

(i) Saturated solution:
a) A solution in which no more solute can be dissolved in a definite amount of the solvent at a given temperature is called saturated solution.
b) E.g. 36 g of sodium chloride in 100 g of water at 25° C forms saturated solution.
c) Further addition of sodium chloride, leaves it undissolved.
(ii) Unsaturated solution:
a) Unsaturated solution is one that contains less solute than that of the saturated solution at a given temperature.
b) E.g. 10 g or 20 g or 30 g of Sodium chloride in 100 g of water at 25°C forms an unsaturated solution.

(i) Chemical Equilibrium: It is state of a reversible chemical reaction in which no change in the amount of reactants and products takes place.
(ii) At equilibrium, Rate of forward reaction = Rate of backward reaction
Characteristics of equilibrium:
(i) In chemical equilibrium, the rates of forward and backward reactions are equal.
(ii) The observable properties such as pressure, concentration, color, density, viscosity etc., of the system remain unchanged with time.
(iii) The chemical equilibrium is a dynamic equilibrium, because both the forward and backward reactions continue to occur even though it appears static externally.
(iv) In physical equilibrium, the volume of all the phases remain constant.

(i) Our body works within the pH range of 7.0 to 7.8.
(ii) Different body fluids have different pH values.
(iii) Any increase or decrease in this value leads to diseases.
(iv) The ideal pH for blood is 7.4.
pH in our digestive system:
(i) HCl present in our stomach helps in digestion.
(ii) During indigestion our stomach produces more acid and this causes pain and irritation.
(iii) pH of the stomach fluid is approximately 2.0.
pH changes as the cause of tooth decay:
(i) pH of the saliva normally ranges between 6.5 to 7.5.
(ii) White enamel coating (calcium phosphate) is a hard substance in our body.
(iii) When the pH value falls below 5.5, it weathers.
(iv) The basic toothpaste neutralises the excess acid and prevents tooth decay.
pH of soil:
(i) Citrus fruits require slightly alkaline soil, rice requires acidic soil and sugarcane requires neutral soil.
pH of rain water:
(i) The pH of rain water is approximately 7.
(ii) If the atmospheric air is polluted with oxides of non-metals, they get dissolved in the rain water and make its pH less than 7.
(iii) As its pH value is less than 7, then it is called acid rain.
(iv) When this rain water reaches river water, the survival of aquatic life becomes difficult.

(i) In a decomposition reaction, a single compound splits into two or more simpler substances by the help of heat. It is called 'Thermolysis'.
(ii) In this type of reaction, the reactant is decomposed by applying heat.
(iii) For example, It is a class of compound to element/element decomposition. i.e. a compound (HgO) is decomposed into two elements (Hg and Oxygen).

(iv) When calcium carbonate is heated, it breaks down in to calcium oxide and carbon dioxide.
(v) It is a type of compound to compound/compound decomposition.
(vi) In thermal decomposition reaction, heat is supplied to break the bonds.
(vii) Such reactions, in which heat is absorbed, are called 'Endothermic reactions'.
\(\mathrm{CaCO}_{3(\mathrm{~s})} \stackrel{\text { heat }}{\longrightarrow} \mathrm{CaO}_{(\mathrm{s})}+\mathrm{CO}_{2}(\mathrm{~g})\)

Smelting (in a Blast Furnace):
(i) The charge consisting of roasted ore, coke and limestone in the ratio 8:4:1 is smelted in a blast furnace by introducing it through the hopper arrangement at the top.
(ii) There are three important regions in the furnace.

a) The Lower Region (Combustion Zone):
(i) The temperature is at \(1500^{\circ} \mathrm{C}\).
(ii) In this region, coke burns with oxygen to form CO₂ when the charge comes in contact with a hot blast of air.
(iii) It is an exothermic reaction since heat is liberated.
\(\mathbf{C}+\mathbf{O}_{2} \underset{\Delta}{\stackrel{1500^{\circ} \mathrm{C}}{\longrightarrow}} \mathrm{CO}_{2}+ Heat\)
b) The Middle Region (Fusion Zone):
(i) The temperature prevails at \(1000^{\circ} \mathrm{C}\).
(ii) In this region, CO₂ is reduced to CO.
\(\mathrm{CO}_{2}+\mathrm{C} \underset{\Delta}{\stackrel{1000^{\circ} \mathrm{C}}{\longrightarrow}} 2 \mathrm{CO}-\text { Heat }\)
(iii) Limestone decomposes to calcium oxide and CO₂.
\(\mathrm{CaCO}_{3} \underset{\Delta}{\stackrel{1000^{\circ} \mathrm{C}}{\longrightarrow}} \mathrm{CaO}+CO_2-\text { Heat }\)
(iv) These two reactions are endothermic due to absorption of heat.
(v) Calcium oxide combines with silica to form calcium silicate slag.
\(\mathrm{CaO}+\mathrm{SiO}_{2} \longrightarrow \mathrm{CaSiO}_{3}\)
c) The Upper Region (Reduction Zone):
(i) The temperature prevails at \(\mathbf{4 0 0 ^ { \circ } \mathrm { C } \text { . }}\)
(ii) In this region carbon monoxide reduces ferric oxide to form a fairly pure spongy iron.
\(\mathrm{Fe}_{2} \mathrm{O}_{3}+3 \mathrm{CO} \stackrel{400^{\circ} \mathrm{C}}{\longrightarrow} 2 \mathrm{Fe}+3 \mathrm{CO}_{2}\uparrow\)
(iii) The molten iron is collected at the bottom of the furnace after removing the slag.
(iv) The iron thus formed is called pig iron.
(v) It is remelted and cast into different molds.
(vi) This iron is called cast iron.

(i) Copper gets covered with a green layer of basic copper carbonate in the presence of CO₂ and moisture.
(ii) \(2 \mathrm{Cu}+\mathrm{O}_{2}+\mathrm{CO}_{2}+\mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{CuCO}_{3} \cdot \mathrm{Cu}(\mathrm{OH})_{2}\)
(iii) Copper reacts with con. \(\mathrm{H}_{2} \mathrm{SO}_{4}\) to from copper sulphate and SO₂.
(iv)  \(\mathrm{Cu}+2 \mathrm{H}_{2} \mathrm{SO}_{4} \rightarrow \mathrm{CuSO}_{4}+\mathrm{SO}_{2} \uparrow+2 \mathrm{H}_{2} \mathrm{O}\)
(v)  So, A is-Copper (Cu)
\(\mathrm{B}\ is \ -\mathrm{CuCO}_{3} \cdot \mathrm{Cu}(\mathrm{OH})_{2}\) Basic copper carbonate.
\(\mathrm{C}\ is \ -\mathrm{CuSO}_{4}\) (copper sulphate)
\(\mathrm{D}\ is \ -\mathrm{SO}_{2}\) (Sulphur oxide)

a) Addition of caustic alkali to bauxite ore:
(i) Bauxite ore is finely ground and heated under pressure with a solution of concentrated caustic soda solution at 150^oC to obtain sodium meta aluminate.
(ii) Al₂O₃ + 2 NaOH → 2 NaAlO₂ + H₂O
(iii) On diluting sodium meta aluminate with water, a precipitate of aluminium hydroxide is formed.
(iv) NaAlO₂ + 2 H₂O → Al(OH)₃ + NaOH
(v) The precipitate is filtered, washed, dried and ignited at 1000^oC to get alumina.
(iv) \(2 \mathrm{Al}(\mathrm{OH})_{3} \stackrel{1000^{\circ} \mathrm{C}}{\longrightarrow} \mathrm{Al}_{2} \mathrm{O}_{3}+3 \mathrm{H}_{2} \mathrm{O}\)
b) (i) Electrolyte : Pure alumina + molten cryolite +fluorspar
(ii) Fluorspar is added to lowers the fusion temperature of electrolyte.

(i) A soap molecule contains two chemically distinct parts that interact differently with water.
(ii) It has one polar end, which is a short head with a carboxylate group (-COONa) and one non-polar end having the long tail made of the hydrocarbon chain.
(iii) The polar end is hydrophilic (Water loving) in nature and this end is attracted towards water.
(iv) The non-polar end is hydrophobic (Water hating) in nature and it is attracted towards dirt or oil on the cloth, but not attracted towards water.
(v) Thus, the hydrophobic part of the soap molecule traps the dirt and the hydrophilic part makes the entire molecule soluble in water.
(vi) These forms micelles in water. The dirt is thus surrounded by the non-polar end of the soap molecules.
(vii) The charged carboxylate end of the soap molecules makes the micelles soluble in water.
(viii) Thus, the dirt is washed away with the soap.

(i) Ethanoic acid reacts with sodium hydroxide to form sodium ethanoate and water
CH₃COOH + NaOH ⟶ CH₃COONa + H₂O
Ethanoic acid               Sodium hydroxide      
(ii) Ethanoic acid reacts with sodium bicarbonate and liberates CO₂, with brisk effervescence.
CH₃COOH + NaHCO₃ ⟶  CH₃COONa  + CO₂  ↑ + H₂O
Ethanoic acid                      Sodium hydroxide
(iii) Ethanol is oxidized to ethanoic acid with alkaline KMnO₄ or acidified K₂Cr₂O₇

(iv) Ethanol is highly inflammable liquid. It burns with oxygen to form carbon dioxide and water.

Homologous series is a group or a class of organic compounds having same general formula and similar chemical properties in which the successive numbers differ by a -CH₂ group.
E.g: Methane - CH₄
Ethane - CH₃CH₃
Propane - CH₃CH₂CH₃
Characteristics:
(i) Each member of the series differs from the preceding or succeeding member by one methylene group (-CH₂) and hence by a molecular mass of 14 amu.
(ii) All members of a homologous series contain the same elements and functional group.
(iii) They are represented by a general molecular formula. e.g. Alkanes, CnH_{2n + 2}
(iv) All the members can be prepared by a common method.

(i) An atom is no longer indivisible.
(ii) Atoms of the same element may have different atomic masses (isotopes ₁₇Cl³⁵, ₁₇Cl³⁷)
(iii) Atoms of different elements may have the same atomic masses (isobars ₁₈Ar⁴⁰, ₁₇Ca⁴⁰)
(iv) Atoms of one element can be transmuted into atoms of other elements. So atom is no longer indestructible. It is called artificial transmutation.
(v) Atoms may not always combine in a simple whole number ratio [Eg: Glucose C₆H₁₂O₆, sucrose C₁₂H₂₂O₁₁)
(vi) Atom is the smallest particle that takes part in a chemical reaction.
(vii) The mass of an atom can be converted into energy (E = mc²).

(i) 27 g of AI
Number of moles = \(\frac{Given\ Mass}{Atomic \ Mass}=\frac{27}{27}=1\)
Number of moles of 27 g of Al is 1 mole
(ii) 1.51 x 10²³ molecules of NH₄Cl
Number of moles = \(\frac{Number \ of \ molecules}{6.023 \times 10^\text{23}}\)
= \(\frac{1.51 \times10^{23}}{6.023 \times10^{23}}\) 
\(\frac{1.51}{6.023}\)
Number of moles of 1.51 x 10²³ molecules of NH₄Cl = 0.25 mole

(i) Herbivores have a more specialised digestive system than that of a carnivore because it is more difficult to digest vegetarian than meat.
(ii) Plant material is difficult to digest, particularly plant cellulose.
(iii) The herbivorous animals have a longer intestine than the carnivorous animals giving more time for digestion.
(iv) The teeth is also designed to grind the grass and plant material rather than the sharp teeth of carnivores designed to tear flesh.

(i) Slime glands are present in the body wall. Their secretion keeps the body moist and slippery so that the host can't remove it easily while it sucks  blood.
(ii) The availability of the host to the leeches is not regular. Hence, a large amount of blood is stored in the crop whenever it gets food. Digestion is also very slow.
(iii) It may take more than a year for the complete digestion after a full meal.
(iv) In leech the ingested blood is stored in crop chambers. It may take more than a year for the complete digestion and absorption of a full meal. So there is no need for an elaborate secretion of digestion juices and enzymes.