Ca(OH)₂ ⇌ Ca²⁺ + 2OH^-
Given that pH = 9
pOH = 14 - 9 = 5
[pOH = - log₁₀ [OH]]
[OH^-] = 10 ^[pOH]
[OH] = 10^-5 M
Ksp = [Ca²⁺] [OH^-]
= 10^-5/2 x (10^-5)²  = 0.5 x 10^-15

t_75% = 2t_50%
t_50% = (t_75%/2) = (60/2) = 30 minutes

[\( \overset{+}{Fe}\)(H₂O)₅\( \overset{+}{NO}\)]²⁺ SO^2-₄
+1 and +1 respectively

(i) p-nitroaniline is prepared from aniline in three stages as follows:

(ii) 
 

(i) Sucrose: D - glucose and D - fructose linked by α. - 1, 2 glycosidic bond.
(ii) Maltose: Two molecules of α. - D - glucose linked by α. - 1, 4 glycosidic bond.
(iii) Lactose: f3 - D - glucose and f3 - D galactose linked by β - 1, 4 glycosidic bond

Nylon - 6,6 can be prepared by mixing equimolar adipic acid and hexamethylene - diamine to form a nylon salt which on heating eliminate a water molecule to form amide bonds.

It is used in textiles, manufacture of cards etc ...

The galvanic cell is represented by a cell diagram, for example, Daniel cell is represented as
\({ Zn }_{ (s) }|{ Zn }_{ (aq) }^{ 2+ }||{ Cu }_{ (aq) }^{ 2+ }|{ Cu }_{ (s) }\)
(i) A single vertical bar (|) represents a phase boundary
(ii) The double vertical bar (||) represents the salt bridge.
(iii) The anode half cell is written on the left side of the salt bridge and the cathode half cell on the right side.
(iv) The anode and cathode are written on the extreme left and extreme right, respectively.
(v) The emf of the cell is written on the right side after cell diagram.

When glycerol is heated with dehydrating agents such as Con H₂SO, KHSO₄ etc .... , it undergoes dehydration to form acrolein.

\(\underset {Phenol} {\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OH}}+\mathrm{Zn}(\text { dust }) \rightarrow \underset {benzene(A)} {\mathrm{C}_{6} \mathrm{H}_{6}}+\mathrm{ZnO}\)

(i) In lyophillic colloids or sols definite attractive force or affinity exists between dispersion medium and dispersed phase. Examples: sols of protein and starch. They are more stable and will not get precipitated easily. 
(ii) In a lyophobic colloids, no attractive force exists between the dispersed phase and dispersion medium. They are less stable and precipitated readily, but cannot be produced again by just adding the dispersion medium. 
Examples: sols of gold, silver, platinum and copper.

Lr Z = 103, is the last element of actinoid series. Its electronic configuration is [Rn]⁸⁶ 5f¹⁴6d¹7S² the possible oxidation state shown by it is +3.

(i) If value of \(\triangle\)G is fur any reaction then to make such reaction spontaneous it is coupled with another reaction of large negative \(\triangle\)G value, so that the sum of two \(\triangle\)G becomes negative. This is known as coupling of reaction.
(ii) In the metallurgy, thermodynamically infeasible reaction is coupled with a reaction which has more negative G, so that net \(\triangle\)G become negative.

(i) The chemical reaction involves breaking of certain existing bonds of the reactant and forming new bonds which lead to the product.
(ii) The net energy involved in this process is dependent on the nature of the reactant and hence the rates are different for different reactants.
Example:
Let us compare the following two reactions that you carried out in volumetric analysis.
1) Redox reaction between ferrous Ammonium Sulphate (FAS) and KMnO₄.
2) Redox reaction between oxalic acid and KMnO₄.
(i) The oxidation of oxalate ion by KMnO₄ is relatively slow compared to the reaction between KMnO₄ and Fe²⁺. In fact heating is required for the reaction between KMnO₄ and Oxalate ion and is carried out at around 60^oC.
(ii) The physical state of the reactant also plays an important role to influence the rate of reactions.
(iii) Gas phase reactions are faster as compared to the reactions involving solid or liquid reactants.
Ex : Na_(s) + I₂(vap)   [Faster]
Na_(s) + I₂(s)   [Slower]
KI_(aq) + Pb(NO3)_2(aq) → PbI₂ (yellow) [Faster]
KI_(s) + Pb(NO3)_2(s) → PbI₂ (yellow)  [Slower]

There are seven types of unit cell, Cubic, tetragonal, orthorhombic, hexagonal, monoclinic, triclinic and rhombohedral. They differ in the arrangement of their crystallographic axes and angles.
i) Cubic: a = b = c; α = β = ૪ = 90^o.

ii) Tetragonal: a = b ≠ c; α = β = ૪ = 90°.

iii) Orthorhombic:  a  ≠ b  ≠ c; α = β = ૪ = 90°.

iv) Hexagonal: a = b ≠ c; α = β = 90^o, ૪ = 120^o. 

v) Monoclinic: a ≠ b ≠ c; α = ૪ = 90^o, β ≠ 90^o, 

vi) Triclinic: a ≠ b ≠ c; α  ≠ β ≠ ૪ ≠ 90^o.

vii) Rhombohedral:  a = b = c; α = β = ૪ ≠ 90^o. 

(i) Borax is used for the identification of coloured metal ions.
(ii) In the manufacture optical and borosilicate glass, enamels and glazes for pottery.
(iii) It is also used as a flux in metallurgy.
(iv) It acts as a good preservative.

Unit of x
\(k=\frac { 1 }{ \rho } .\frac { l }{ A } \left( \frac { 1 }{ ohm } .\frac { m }{ { m }^{ 2 } } \right) \)
= ohm^-1 m^-1 = mho m^-1 (or) Sm^-1

\(\mathrm{Hg}_{2} \mathrm{Cl}_{2(\mathrm{~s})} \rightleftharpoons \mathrm{Hg}_{2}^{2+} \text { (aq) }+2 \mathrm{Cl^-}_{(\mathrm{aq})}\\ s \quad \quad \quad \quad \quad \quad s \quad \quad \quad \quad \quad 2s\)
\(\mathrm{K}_{\mathrm{sp}} =\left[\mathrm{Hg}_{2}^{2+}\right]{\left[\mathrm{Cl}^{-}\right]^{2}}  \)
\(=(\mathrm{s})(2 \mathrm{~s})^{2} \)
\(\mathrm{~K}_{\mathrm{sp}} =4 \mathrm{~s}^{3}\)

Conjugate Pairs:
\((a) \mathrm{HS}_{\text {(aq) }}^{-} \& \mathrm{H}_{2} \mathrm{~S}_{\text {(aq) }} \) \((b) \mathrm{HF}_{\text {(aq) }} \& \mathrm{~F}_{\text {(aq) }}^{-} \)
\((a) \mathrm{HPO}_{4}^{2-} \& \mathrm{PO}_{4}^{3-} \) \((b) \mathrm{SO}_{3}^{2-} \& \mathrm{HSO}_{3}^{-} \)
\((a) \mathrm{NH}_{4}^{+} \& \mathrm{NH}_{3} \) \((b) \mathrm{CO}_{3}^{2-} \& \mathrm{HCO}_{3}^{-}\)

(i) I Order reaction
(ii) S^-1
(iii) \({ t }_{ \frac { 1 }{ 2 } }\) = 0.693/k

This is due to,
(i) Lowbond dissociation enthalpy of F-F-bond
(ii) High hydration enthalpy of F^-.

The best known examples of this type of isomerism occur for chromium chloride CrCI₃.6H₂O which may contain 4, 5, (or) 6 coordinated water molecules.
[Cr(H₂O)₄CI₂]Cl.2H₂O -Bright green
Tetraaquadichlorochromium(III)chloride dihydrate
[Cr(H₂O)₅CI]Cl₂.H₂O - grey-green
Pentaaquachlorochromium(III) chloride monohydrate
[Cr(H₂O)₆]CI₃ Violet
Hexaaquachromium (III) chloride 

(i) Zeolites are three-dimensional crystalline solids containing Al, Si and O in their regular three dimensional framework.
(ii) They are hydrated sodium alumino silicates with general formula Na₂O(AI₂O₃).·x(SiO₂)·yH₂O
(x = 2 to 10; y = 2 to 6).
(iii) Zeolites have porous structure in which the monovalent sodium ions and water molecules are loosely held.
(iv) The Si and Al atoms are tetrahedrally coordinated with each other through shared oxygen atoms.
(v) Zeolites are similar to clay minerals but they differ in their crystalline structure.
(vi) Zeolites have a three dimensional crystalline structure looks like a honeycomb consisting of a network of interconnected tunnels and cages.
(vii) Water molecules moves freely in and out of these pores but the zeolite framework remains rigid
(viii) Another special aspect of this structure is that the pore/channel sizes are nearly uniform, allowing the crystal to act as a molecular sieve.

(i) Compound (A) does not reduce Fehling's solution, so it is benzaldehyde.
(ii) Benzaldehyde (A) reacts with acetone in the presence of NaOH to give on a, p unsaturated compound (B).
\(\\ \\ \\ \underset { (A) }{ { C }_{ 6 }{ H }_{ 5 }CHO } +{ CH }_{ 3 }-{ COCH }_{ 3 }\overset { NaoH }{ \longrightarrow } \underset { (B) }{ { C }_{ 6 }{ H }_{ 5 } } -\underset { Acetone }{ CH=CH-{ COCH }_{ 3 } } \) 
(iii) (A) reacts with dimethyl aniline in the presence of conc. H₂SO₄ to give compound (C).

Compound	Compound Name	Formula
A	Benzaldehyde	C6H5CHO
B	Benzal acetone	C6H5CH = CH-COCH3
C	Triphenyl methane dye

Condensation Methods:
Various chemical methods for the formation of colloidal particles.
(i) Oxidation:
Sols of some non-metals are prepared by this method. (a) When hydroiodic acid is treated with iodic acid, 12 sol is obtained.
\({ HIO }_{ 3 }+5HI\longrightarrow { 3H }_{ 2 }O+{ I }_{ 2 }\) (Sol)
(ii) Reduction:
Many organic reagents like phenyl hydrazine, formaldehyde, etc are used for the formation of sols. For example: Gold sol is prepared by reduction of auric chloride using formaldehyde.
\(2{ AuCl }_{ 3 }+3HCHO+{ 3H }_{ 2 }O\longrightarrow 2Au\left( sol \right) +6HCl+3HCOOH\) 
(iii) Hydrolysis: 
Sols of hydroxides of metals like chromium and aluminium can be produced by this method.
For example,
\({ FeCl }_{ 3 }+3H_{ 2 }O\longrightarrow Fe(OH)_{ 3 }+3HCl\) 
(iv) Double decomposition: 
For the preparation of water insoluble sols this method can be used. When hydrogen sulphide gas is passed through a solution of arsenic oxide, a yellow coloured arsenic sulphide is obtained as a colloidal solution.
\({ As }_{ 2 }{ O }_{ 3 }+3{ H }_{ 2 }S\longrightarrow { AS }_{ 2 }{ S }_{ 3 }+{ 3H }_{ 2 }O\) 
(v) Decomposition:
When few drops of an acid is added to a dilute solution of sodium thio sulphate, the insoluble free sulphur produced by decomposition of sodium thiosulphate accumulates into small, clusters which impart various colours blue, yellow and even red to the system. depending on their growth within the size of colloidal dimensions.
\({ S }_{ 2 }{ O }_{ 3 }^{ 2- }+{ 2H }^{ + }\longrightarrow \underset{sol}S+{ H }_{ 2 }O+{ SO }_{ 2 }\) 
By exchange of solvent:
(i) Colloidal solution of few substances like phosphorous or sulphur is obtained by preparing the solutions in alcohol and pouring them into water.
(ii) As they are insoluble in water, they form colloidal solution.
P in alcohol + water ⟶ Psol.

On the basis of magnetic properties, materials can be broadly classified as
(a) paramagnetic materials
(b) diamagnetic materials, besides these there are ferromagnetic and antiferromagnetic materials
(i) Materials with no elementary magnetic dipoles are diamagnetic, in other words a species with all paired electrons exhibits diamagnetism.
(ii) This kind of materials are repelled by the magnetic field because the presence of external magnetic field, a magnetic induction is introduced to the material which generates weak magnetic field that oppose the applied field
(iii) Paramagnetic solids having unpaired electrons possess magnetic dipoles which are isolated from one another.
(iv) In the absence of external magnetic field, the dipoles are arranged at random and hence the solid shows no net magnetism.
(v) But in the presence of magnetic field, the dipoles are aligned parallel to the direction of the applied field and therefore, they are attracted by an external magnetic field.
(vi) Ferromagnetic materials have domain structure and in each domain the magnetic dipoles are arranged.
(vii) But the spin dipoles of the adjacent domains are randomly oriented.
(viii) Some transition elements or ions with unpaired d electrons show ferromagnetism.

Oxidising property of H₂SO₄: 
Sulphuric acid is an oxidising agent as it produces nascent oxygen as shown below.
\({ H }_{ 2 }{ SO }_{ 4 }\longrightarrow { H }_{ 2 }O+\underset { nascentoxygen }{ { SO }_{ 2 } } +\left( O \right) \)
Sulphuric acid oxidises elements such as carbon, sulphur and phosphorus. It also oxides bromide and iodide to bromine and iodine respectively.
C + 2H₂SO₄ \(\longrightarrow \) 2SO₂ + 2H₂O + CO₂
S + 2H₂SO₄ \(\longrightarrow \) 3SO₂ + 2H₂O
P₄ + 10H₂SO₄ \(\longrightarrow \) 4H₃PO₄ + 10SO₂ + 4H₂O
H₂S + H₂SO₄ \(\longrightarrow \) SO₂ + 2H₂O + S
H₂SO₄ + 2HI \(\longrightarrow \) SO₂ + H₂O + I₂
H₂SO₄ + 2HBr \(\longrightarrow \) 2SO₂ + 2H₂O + Br₂

(i) The colour develops because of the presence of electrons in the 8 anionic sites.
(ii) These electron absorb energy from the visible region of radiation and get excited. 
(iii) For example when crystals of NaCl are heated in an atmosphere of sodium vapours, the sodium atoms get deposited on the surface of the crystal and the deposited Na atoms.
(iv) During this process, the Na atoms on the surface lose electrons to form Na⁺ ions 
(v) These electrons get excited by absorbing energy from the visible light and impart yellow colour to the crystals.

(i) [NiCI₄]^2-
IUPAC name - Tetrachloridonickelate (II) ion
(ii) Ni²⁺ = 3d⁸,4s⁰

Cl^- being a weak field ligand cannot pair up the unpaired electron. So, it is sp³ hybridised, and it has tetrahedral geometry.