Showing posts with label Notes and keys. Show all posts
Showing posts with label Notes and keys. Show all posts

Monday, February 3, 2014

Class 11 Chemistry Notes GOC - Intermediates of Organic Compounds

By Sonu Kumar Gupta   Posted at  12:47 AM   Notes and keys No comments

Intermediates of Organic Compounds
Class 11 Chemistry Notes GOC   Intermediates of Organic Compounds
Electronic Displacement Effect:
It is an effect which exists due to the displacement of electron in specie.

These effects can affect stability of compounds and its properties like acidic nature and basic nature. It can also affect the strength of acidic and basic nature of any compound.
Electronic Displacement Effect can be basically divided into two parts:-


  1. Permanent effect
  2. Temporary effect
Permanent effect includes:
  1. Inductive effect
  2. Mesmeric (resonance) effect
  3. Hyper conjugation whereas
Temporary effect:
  1. Electromeric effect
  2. Inductomeric effect


Class 11 Chemistry Notes General Organic Chemistry

By Sonu Kumar Gupta   Posted at  12:45 AM   Notes and keys No comments

General Organic Chemistry is like soul for preparation of organic chemistry.
First we will see how bond breaks and what the different reasons behind bond breaking.
There are basically two types of bond fission:
  1. Homolytic Bond Fission
  2. Heterolytic Bond Fission
Homolytic Bond Fission:
Homolysis: The bond cleavage in which each bonded atom gets their own contribution
Class 11 Chemistry Notes General Organic Chemistry
  • Cleavage takes place due to HELP (H = Heat, E = Electricity, L = Light, P = Peroxide)
  • Favored when Electro negativity difference is zero.
  • Cleavage takes place in non polar solvent.
Heterolytic Bond Fission:
Class 11 Chemistry Notes General Organic Chemistry
  • It is formed when the electronegativity difference between the bonded atoms is high.
  • Formation is favored by polar solvent
Class 11 Chemistry Notes General Organic Chemistry
  • Positive charge of the solvent attracts the Negative pole of compound and the
  • Negative pole of the solvent attracts Positive, and the bond breaks.


Class 11 Chemistry Notes Stocihiometry - Important Question Answers

By Sonu Kumar Gupta   Posted at  12:43 AM   Notes and keys No comments

Ex. A volume of 12.53 ml of 0.051 M SeO2 reacts exactly with 25.5 ml of 0.1 M CrSO4 which is oxidized to Cr3+ To what oxidation state was the selenium converted b the reaction.
Sol.
Class 11 Chemistry Notes Stocihiometry   Important Question Answers

Ex. In basic solution CrO42- ion oxidizes S2O32- ion to form Cr(OH)4- and SO42- ions respectively. How many ml of 0.154 Na2CrO4 solutions are required just to react with 40 ml of 0.246 M Na2S2 O3 solutions.
Sol.
Class 11 Chemistry Notes Stocihiometry   Important Question Answers
Ex. What mass of N2H4 can be oxidized to N2 by 24 gm of K2CrO4 which is reduced to
Sol.
Class 11 Chemistry Notes Stocihiometry   Important Question Answers

Ex. The ion An+ is oxidized to AO3- by MnO4- changing to Mn2+ in acid medium. Given that mole of An+ required mole of MnO4-. What is the value of n.
Sol.
Class 11 Chemistry Notes Stocihiometry   Important Question Answers

Ex. 25 ml of 0.17 M HSO3- in strongly acidic solution required the addition of 16.9 ml of 0.01 M MnO4- for its complete oxidation to SO42-. In neutral solution it requires 28.6 ml. Assign oxidation no. of ‘Mn’ in each of the products.
Sol.
Class 11 Chemistry Notes Stocihiometry   Important Question Answers
Ex. A given amount of Fe2+ is oxidized by x mol of MnO4- in acidic medium. Calculate mol of Cr2O72- required same amount of Fe2+ in acidic medium
Sol.
Class 11 Chemistry Notes Stocihiometry   Important Question Answers
Ex. Calculate mol of (a) MnO4- and (b) Cr2O72- to oxidize 1 mol of FeC2O4 (ferrous oxalate) in acidic medium.
Sol.
Class 11 Chemistry Notes Stocihiometry   Important Question Answers

Ex. A mixture of Na2C2O4 and KHC2O4. H2C2O4 required equal volume of 0.1 M KMnO4 and 0.1 M NaOH separately. What is the molar ratio of Na2C2O4, KHC2O4 and H2C2O4 in the mixture?
Sol.
Class 11 Chemistry Notes Stocihiometry   Important Question Answers

Ex. 5.5 gm of a mixture of FeSO4. 7H2O and Fe2 (SO4)3. 9H2O requires 5.4 ml of 0.1 N KMnO4 solutions for complete oxidation. Calculate the no. of gm moles of hydrated ferric sulphate in the mixture?
Sol.
Class 11 Chemistry Notes Stocihiometry   Important Question Answers


Class 11 Chemistry Notes Stocihiometry - Glossary

By Sonu Kumar Gupta   Posted at  12:41 AM   Notes and keys No comments

Aliquot. A portion of the whole, usually a simple fraction. A portion of a sample withdraw from a volumetric flask with a pipet is called as aliquot.
Analytical concentration, The total number of moles per litre of a solute regardless of any reactions that might occur when the solute dissolves. Used synonymously with formality.
Equivalent. The amount of a substance which furnishes or reacts with 1 of H+ (acid-base), 1 mol of electrons (redox), or 1 mol of a univalent cation (precipitation and complex formation).
Equivalent weight. The weight in grams of one equivalent of a substance.
Equivalence point. The point in a titration where the number of equivalents of titrant is the same as the number of equivalents of analytic.
End point.The point in a titration where an indicator changes color.
Formula weight. The number of formula weights of all the atoms in the chemical formula of a substance.
Formality. The number formula weights of solute per liter of solution; synonymous with analytical concentration.
Indicator. A chemical substance which exhibits different colors in the presence of excess analyte or titrant.
Normality. The number of equivalents of solute per litre of solution.
Primary standard. A substance available in a pure form or state of known purity which is used in standardizing a solution.
Standardization. The process by which the concentration of a solution is accurately acertained.
Standard solution. A solution whose concentration has been accurately determined.
Titrant. The reagent (a standard solution) which is added from a buret to react with the analyte.


Class 11 Chemistry Notes Stocihiometry - The Atlas

By Sonu Kumar Gupta   Posted at  12:40 AM   Notes and keys No comments

THE ATLAS : A GOOD WAY TO REVISE CHAPTER
Class 11 Chemistry Notes Stocihiometry   The Atlas


Class 11 Chemistry Notes Stocihiometry -Double indicator acid-base titration

By Sonu Kumar Gupta   Posted at  12:37 AM   Notes and keys No comments
Double indicator acid-base titration:
In the acid-base titration the equivalence point is known with the help of indicator which changes its color at the end point. In the titration of polyacidic base or polybasic acid there are more than one end point. One indicator is not able to give color change at every end point. So to find out each end point we have to use more than one indicator. For example in the titration of Na2CO3 against HCl there are two end points.
Na2CO3 + HCl → NaHCO3 + NaCl

NaHCO3 + HCl → H2CO3 + NaCl
When we use phenolphthalein in the above titration it changes its color at first end point when NaHCO3 is formed and with it we cannot know second end point. Similarly with methyl orange it changes its color at second end point only and we cannot know first end point. It is because all indicator changes color on the basis of pH of medium. So in titration of against acid phenolphthalein cannot be used.
Class 11 Chemistry Notes Stocihiometry   Double indicator acid base titration

A sample contains NaOH, Na2CO3& NaHCO3. This solution is titrated with HCl or H2SO4
(i) When phenolphthalein (HPh) is used as indicator the reaction are given below.

Na2CO3 + HCl → NaHCO3 + NaCl

This is the half neutralization of Na2CO3

NaHCO3 + HCl → X

NaOH + HCl → NaCl + H2O

Hence

Meq. Of HCl = Meq. Of NaOH + (1/2) Meq. Of Na2CO3
(ii) When methyl orange (MeOH) is used as indicator

Na2CO3 + 2HCl → 2NaCl + H2O + CO2

This is the complete neutralization

NaHCO3 + HCl → NaCl + H2O + CO2

NaOH + HCl → NaCl + H2O

in this case

Meq. Of HCl = Meq. Of NaOH + Meq. Of Na2CO3 + Meq. Of NaHCO3
(iii) If MeOH is added after the first end point obtained from HPh

NaHCO3 + NaHCO3 + HCl → NaCl + H2O + CO2

Produced original

Meq. Of HCl = Meq. Of NaHCO3 (produced) + Meq. Of NaHCO3 (original)
Note:
When we carry out dilution of solution, Meq eq. Milli mole or mole of substance does not change because they represent amount of substance, however molar concentration may change.
Ex.1 A solution contains a mixture of Na2CO3 and NaOH. Using phenolphthalein as indicator 25 ml. of mixture required 19.5 ml of 0.995 N HCl for the end point. With methyl orange. 25 ml of solution required 25 ml. of the same. HCl for the end point. Calculate grams per liter of each substance in the mixture.
Sol.
Let a & b are the Meq. Of Na2CO3 and NaOH respectively

When phenolphthalein in is used as indicator

(1/2) Meq. Of Na2CO3 + Meq. of NaOH = Meq. of HCl

(a/2) + b = 19.5 × 0.995

(a/2) + b = 19.4 …(1)

When MeOH is used as indicator

Meq. Of Na2CO3 + Meq. Of NaOH = Meq. Of HCl

a + b = 25 × 0.995

a + b = 24.875 …(2)

From (1) & (2)

(a/2) = 5.475 Þ a = 10.95

B = 24.875 – 10.95 = 13.925

Wt of Na2CO3/lit = (10.95/25) × 10-3 × (106/3) × 1000 = 23.2 gm/lit

Wt of NaOH/lit = b × 10-3 × 84/25 × 1000 = 22.28 gm/lit Ans.
Ex.2 2.5 g of a mixture containing CaCO3, Ca(HCO3)2 and NaCl was dissolved in 100 mL water and its 10 mL portion required 10 mL 0.05 M H2SO4 solution to reach the phenolphthalein end point. An another 10 mL portion of the same stock solution required 32.35 mL of the same acid solution to reach the methyl orange end point. Determine mass percentage of CaCO3 and Ca (HCO3)3in the original mixture.
Sol.
Let a and b are the Meq. of CaCO3 and Ca(HCO3)2 respectively.

When HPh is used in indicater then only CaCO3 will react with H2SO4

Meq. of H2SO4 = (1/2) Meq. of CaCO3

Meq. of H2SO4 = ((10 × 0.05 × 100 × 2)/10) = 10

Meq. of CaCO3 = 20

When MeOH is used as indicator

Then Meq. or CaCO3 + Meq. of Ca(HCO3)2 = Meq. of H2SO4

a + b = ((32.35 × 0.05 × 2)/10) × 100

a + b = 32.35

b = 12.5

wt. of CaCO3 = a × 10-3 × 100/2

= 1 gm

wt. of Ca(HCO3)2 = b × 10-3 × 162/2 = 1 gm

% of CaCO3 = (1/2.5) × 100 = 40%

% of Ca(HCO3)2 = (1/2.5) × 100 = 40%
Ex.3. 6.4 g of a pure monobasic organic acid is burnt completely in excess of oxygen and CO2 evolved is absorbed completely in one liter of an aqueous solution of NaOH. A 10 mL portion of this solution required 14.5 mL of a normal HCl solution to reach the phenolphthalein end point. Another 10 mL portion of the same solution required 18 mL of the same HCl solution to reach the methyl orange end point. If the organic acid contains 25% oxygen by weight, deduce the empirical formula of this acid and strength of original NaOH solution
Sol.
Class 11 Chemistry Notes Stocihiometry   Double indicator acid base titration
Let 100 ml of solution contains a Meq. of NaOH & b Meq. of Na2CO3

When HPh is used as indicator then

Meq. of NaOH + 1/2 Meq. of Na2CO3=Meq. of HCl
Class 11 Chemistry Notes Stocihiometry   Double indicator acid base titration
Ex.4 A solution contains Na2CO3 and NaHCO3. 10 mL of the solution requires 2.5 mL of for neutralisation using phenolphthalein as an indicator. Methyl organge is added when a further 2.5 mL of 0.2 M H2SO4 was required. Calculate the amount of Na2CO3 and NaHCO3 in one litre of the solution.
Sol.
Class 11 Chemistry Notes Stocihiometry   Double indicator acid base titration


Class 11 Chemistry Notes Stocihiometry -Calculation of Chlorine from a Sample of Bleaching Powder

By Sonu Kumar Gupta   Posted at  12:35 AM   Notes and keys No comments

The weight % of available Cl2 from the given sample of bleaching powder on reaction with dil acids or CO2 is called available chlorine.
CaOCl2 + H2SO4 → CaSO4 + H2O + Cl2

CaOCl2 + 2HCl → CaCl2 + H2O + Cl2

CaOCl2 + 2CH3COOH → Ca (CH3COO) 2 + H2O + Cl2

CaCOl2 + CO2 → CaCO3 + Cl2
Method of determination:
Bleaching powder + CH3COOH + KI (starch/Hypo)end point

Meq. Of I2 = Meq. Of Cl2 = Meq. Of Hypo solution

% of Cl2 = (3.55 × x × V (mL)/W (g))

Where x=Molarity of hypo solution

V =mL of hypo solution used in titration.
Ex.1. 10 gm sample of bleaching powder was dissolved into water to make the solution on liter. To this solution 35 mL of 1.0 M Mohr salt solution was added containing enough H2SO4. After the reaction was complete, the excess Mohr salt required 30 mL of 0.1 M KMnO4 for oxidation. The % of available Cl2 approximately is (mol wt=71)
Sol.2. Meq. Of Mohr’s salt =35×1×1=35

Meq. Of KMnO4=Meq. Of excess Mohr salt=30×0.1×5=15

Meq. Of Mohr salt reacted with bleaching powder =35-15=20

Meq. Of Cl2=20

Wt. of Cl2 = 20 × 10-3 × (71/2) = 0.71 gm

% of Cl2 = (0.71/10) × 100 = 7.1% Ans.


Class 11 Chemistry Notes Stocihiometry - Equivalent Concept and Titration

By Sonu Kumar Gupta   Posted at  12:33 AM   Notes and keys No comments

Back titration
Back titration is used in volumetric analysis to find out excess of reagent added by titrating it with suitable reagent. It is also used to find out percentage purity of sample. For example in acid-base titration supposes we have added excess base in acid mixture. To find excess base we can titrate the solution with another acid of known strength.
Ex.2 20 g. of a sample of Ba(OH)2 is dissolved in 50 ml. of 0.1 N HCl solution. The excess of HCl was titrated with 0.1 N NaOH. The volume of NaOH used was 20 cc. Calculate the percentage of Ba(OH)2 in the sample.
Sol. Milli eq. of HCl initially =50×0.1=5
Milli eq. of NaOH consumed = Milli eq. of HCl in excess =20×0.1=2
∴ Milli eq. of HCl consumed = Milli eq. of Ba (OH)2=5-2=3
∴ eq. of Ba(OH)2 = 3 / 1000 = 3 × 10-3
Mass of Ba (OH)2 = 3 × 10-3 × (171/2) = 0.2565 g
% Ba (OH)2=(0.2565/20)×100=1.28% Ans.
Ex.3 4.0 g of monobasic, saturated carboxylic acid is dissolved in 100 mL water and its 10 mL portion required 8.0 mL 0.27 M NaOH to reach the equivalence point. In an another experiment, 5.0 g of the same acid is burnt completely and CO2 produced is absorbed completely in 500 mL of a 2.0 N NaOH solution. A 10 mL portion of the resulting solution is treated with excess of BaCl2 to precipitate all carbonate and finally titrated with 0.5 N H2SO4 solution. Determine the volume of the acid solution that would be required to make this solution neutral.
Sol. Meq. Of NaOH=8×0.27=Meq. Of acid for 10 ml of acid solution
Meq. Of acid for 100 ml of solution
= (8 × 0.27 × 1000)/10 = (4/M) × 103
M (acid) = 4/(8 × 0.27 × 10) × 1000 = 185.2
Formula of acid. = CnH2nO2
Þ M = 14n + 32 = 185.2
Þ n = 11
Now 5g acid will produce (5/185.2) × 11 = (55/185.2) mol CO2 after complete combustion.
2NaOH + CO2 → Na2CO3 + H2O
Total mass of NaOH available = 500 × 2 × 10-3 = 1.0 mole
Moles of NaOH left unreacted = 1-(2 × 55/185.2) = (76/185.2) in 500 mL
Þ Molarity of NaOH after precipitation of Na2CO3 = 0.812
Therefore, 0.812 × 10 = 0.5 × V
Þ V = 16.24 mL Ans.
Precipitation titration:
In ionic reaction we can know strength of unknown solution of salt by titrating it against a reagent with which it can form precipitate. For example NaCl strength can be known by titrating it against AgNO3 solution with which it forms white ppt. of AgCl.
So Meq. Of NaCl at equivalence point =Meq. Of AgNO3 used= Meq. Of AgCl formed
Ex.4 A complex of cobalt with ammonia is analyzed for determining its formula, by titrating it against a standardized acid as follows:
Co (NH3) x Cl3 (aq) + HCl → NH+4(aq) + Co3+ (aq) + Cl-(aq)
A 1.58 g complex required 23.63 mL 1.5 M HCl to reach the equivalence point. Determine formula. If the reaction mixture at equivalence point is titrated with excess of AgNO3 solution, what mass of AgCl will precipitate out?
Sol. The balanced chemical reaction is:
Co(NH3)x Cl3 + xHCl → xNH+4 + Co3+ + (x + 3) Cl-
Class 11 Chemistry Notes Stocihiometry   Equivalent Concept and Titration


Class 11 Chemistry Notes Stocihiometry -Disproportionate Reactions and Law of Chemical equivalence

By Sonu Kumar Gupta   Posted at  12:30 AM   Notes and keys No comments
Disproportionate Reactions:
A redox reaction in which a same element present in a particular compound in a definite oxidation state is oxidized as well as reduced simultaneously is a disproportionate reaction.
Class 11 Chemistry Notes Stocihiometry   Disproportionate Reactions and Law of Chemical equivalenc
n factor of overall reaction = n1 × n2 / n1 + n2

Ex.1
MnO4- + 8H+ + 5e → Mn+2 + 4H2O

n factor of KMnO4 = 5
EX.2
Find the n factor of Na2S2O3 in the following reactions.

(a) Na2S2O3 + I2 → NaI + Na2S4O6

Sodium thio sodium tetra

Sulphate thionate

(b) Na2S2O3 + I2 → NaI + Na2SO4
Sol.
(a) Change in oxidation number of sulphur=|+2-2.5|=0.5

Change in oxidation number per molecule =0.5×2

∴ n factor of Na2S2O3 = 1
(b) Change in oxidation number of sulphur=|2-6|=4

Change in oxidation number per molecule =4×2

∴ n factor of Na2S2O3 = 8
=> Consider the salt Ax By to undergo a reaction so that the element A undergoes a change in O.S. but is present in more than one product with the same oxidation state i.e. A+cxBy → A+faBy + A+fgH

(the superscripts denote the oxidation state of the respective elements).
∴ n=|xc-xf|
=> Salts that react in such a way that more than one type of atom in the salt undergoes oxidation state Change.

A+cxBy → A+faE + JxB-1
In this case both A and B are changing their O.SO. ‘s and both of them are either getting oxidized or reduced. In such a case n factor of the compound is the sum of the individual n factors of A and B. i.e.|xc-xf| + |-xC- (-yi)|. Then n factor of A can be understood which is |xc-xf|. The n factor of B is |-xc-(-yi)|

Law of Chemical equivalence:
It states that in any chemical reaction the equivalents of all the reactants and products must be same.
2A+3B→4C
Eq. of A=Equivalents of ‘B’=Equivalents of ‘C’
Equivalents of ‘A’ = (Weight of ‘A’)/Equivalent weight of ‘A’
Or Equivalents of ‘A’ = no. of moles of ‘A’ x n-factor
A + B + C → product
If A & B do not react with each other but C react with both A & B then
Gm eq. of A + Gm eq. of B= gm eq. of C
Or
Meq. Of A + Meq. Of B = gm Meq. Of C


Class 11 Chemistry Notes Stocihiometry - N factor calculation

By Sonu Kumar Gupta   Posted at  12:24 AM   Notes and keys No comments
N factor here we mean a conversion factor by which we divide molar mass of substance to get equivalent mass and it depends on nature of substance which varies from one condition to another condition. We can divide n-factor calculation is two category.
In case of non-redox reaction.
(a) n factor of acid =Basicity of the acid

Basicity: Number of replaceable H+ ion.
Ex.1
n factor of HCl = 1

n factor of CH3COOH=1

n factor of H2SO4=2
(b)n factor of base= acidity of the base
Acidity: Number of replaceable OH- ion.

Ex.2
n factor of NaOH=1

n factor of Ca(OH)2=2

n factor of Al(OH)3=3

n factor of B(OH)3=1 (because it is a mono basic acid)
(c) n factor Salt: Total number of positive or negative charge.

Ex.3
n factor of NaCl=1

n factor of Na2SO4=2

n factor of K2SO4. Al2 (SO4)3. 24H2O = 8

Ex.4
Find the n factor of H3PO4 in the following reaction.

H3PO4 + Ca (OH)3 → CaHPO4 + 2H2O
Sol.
Basicity of H3PO4 in the above reaction is 2

∴ the n factor of H3PO4 is 2
In case of redox reaction
(a) From oxidation number
n factor of oxidizing or reducing agent=change in oxidation number per molecule.
⇒ consider a salt AxBy in which the O.S. of A is +c. It changes to a compound AdE in which the O.S. of A is +f. Here we are assuming that B does not undergo any change in O.S. A+cxBy → A+fdE (Obviously AxBy must have reacted with some other substance to produce the product AdE. That means other substance has the atom E in it.) The ‘n’ factor is = |xc-xf|.

Ex.5
Find the n factor of KMnO4 in different medium.
Sol.
(i) In acidic medium

KMnO4→Mn+2

Change in oxidation number of Mn=+7-2=5

∴ the n factor of KMnO4=5
(ii) Basic medium

KMnO4→K2MnO4

N factor of KMnO4 = +7 – 6 = 1
(iii) Neutral medium

KMnO4 → MnO2

N factor of MnO2 = +7 – 4 = 3
(b)From ion electron method:
N factor = total number of electrons transferred per mole of the reactant


Class 11 Chemistry Notes Stocihiometry - Balancing of Equations

By Sonu Kumar Gupta   Posted at  12:22 AM   Notes and keys No comments
Balancing of Equations:
  1. Ion-electron method
  2. Oxidation number method

    [Concept involved that in any chemical reaction e- cannot be produced so no. of e- s in O.H. & R.H. should be same]
Note : To predict the product of reaction remember:
  • Free halogen on reduction gives halide ion (F2 → F-)
  • Alkali metals on oxidation give metallic ion with +1 oxidation state.
  • In alkaline medium KMnO4 is reduced to K2MnO4 but in strong alkaline or neutral medium it reduces of Mn+4
  • In acid solution KMnO4 is reduced to Mn2+
  • H2O2 on reduction gives water and on oxidation gives oxygen.
  • Dichromate ion in acid solution is reduced to Cr3+.
Nature of Oxides Based on Oxidation Number:
Lowest oxidation state → Basic (MnO)

Intermediate oxidation state → Amphoteric (Mn3O4, MnO2)

Highest oxidation state → Acidic (Mn2O7)
Rules For Assigning Oxidation Number:
  1. Oxidation number of free elements or atoms is zero.
  2. Oxidation number of allotropes is zero.
  3. Oxidation number of atoms in homo-nuclear molecules is zero.
  4. Oxidation number of mono-atomic ions is equal to the algebraic charge on them.
  5. Oxidation number of F in compounds is – 1
  6. Oxidation number of H in its compounds is +1, except in metal hydrides where it is-1
  7. Oxidation number of O is-2in its compound, but in and in peroxides it is 1 and -0.5 in KO2
  8. Oxidation number of alkali metals in their compounds + 1.
  9. Oxidation number of alkaline earth metals in their compounds is + 2.
  10. The sum of oxidation number of all the atoms in a molecule should be zero and in an ion equal to its charge.
Average Oxidation Number : Find Oxidation Number of Fe in Fe3O4.
Fe3O4 is FeO. Fe2O3

O.N. of Fe in FeO is + 2 ; O.N. of Fe in Fe2O3 is + 3.
Therefore average O.N. of three Fe atoms (+2 + 2x (+3))/3 = +(8/3)


Class 11 Chemistry Notes Stocihiometry - Oxidation and Reduction

By Sonu Kumar Gupta   Posted at  12:19 AM   Notes and keys No comments

Oxidation Number:
It is the charge (real or imaginary) which an atom appears to have when it is in combination. It may be a whole no. or fractional. An element may have different values of oxidation number depending. It depends on nature of compound in which it is present. There are some operational rules to determine oxidation number.
Oxidation:
Addition of oxygen, removal of hydrogen, addition of electro-negative element, removal of electropositive element, loss of electrons, increase in oxidation number (de – electro nation).
Reduction:
Removal of oxygen, addition of hydrogen, removal of electronegative element, addition of electro positive element, gain of electrons, decrease inoxidation number (electro nation).
Redox Reactions:
A reaction in which oxidation & reduction occur simultaneously.
Oxidising Agents:
(oxidants, oxidizers). They oxidise others, themselves are reduced & gain electrons. Eq. O2, O3, HNO3, MnO2, H2O2, halogens, KMnO4, K2Cr2O7, KIO3, CIO3, FeCl3, NaOCl hydrogen ions.

[Atoms are present in their higher oxidation state.
Reducing Agents:
H2, molecular form is weak reducing agent but Nascent hydrogen is powerful. C, CO, H2S, SO2, SnCl2, sodium thio Sulphate, Al, Na, CaH2, NaBH4, LiAlH4. They reduce others, themselves get oxidised & lose electrons. Also called reductants or reducers.

[Atoms are present in their lower oxidation state.]
Both oxidizing & Reducing Agents:
SO2, H2O2, O3, NO2, etc.



Sunday, January 26, 2014

CBSE class 11 chemistry notes

By Sonu Kumar Gupta   Posted at  1:35 AM   Notes and keys 2 comments
Chemistry Notes Some Basic Concepts of Chemistry
CBSE class 11 Chemistry Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book.



Chemistry Notes Structure of Atom
Chemistry Notes Structure of Atom CBSE class 11 Chemistry Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book.

Chemistry Notes Classification of Elements
Chemistry Notes Classification of Elements CBSE class 11 Chemistry Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book.


Chemistry Notes Chemical Bonding and Molecular Structure

Chemistry Notes Chemical Bonding and Molecular Structure CBSE class 11 Chemistry Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book.


Chemistry Notes States of Matter
Chemistry Notes States of Matter CBSE class 11 Chemistry Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book.



Chemistry Notes Thermodynamics

Chemistry Notes Thermodynamics CBSE class 11 Chemistry Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book.



Chemistry Notes Equilibrium

Chemistry Notes Equilibrium CBSE class 11 Chemistry Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book.



Chemistry Notes Redox Reaction 01

Chemistry Notes Redox Reaction 01 CBSE class 11 Chemistry Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book.



Chemistry Notes Redox Reaction 02

Chemistry Notes Redox Reaction 02 CBSE class 11 Chemistry Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book.



Chemistry Notes Hydrogen
Chemistry Notes Hydrogen CBSE class 11 Chemistry Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book.
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CBSE Class 11 physics notes

By Sonu Kumar Gupta   Posted at  1:28 AM   Notes and keys No comments
Key Notes Physical World and Measurement
Key Notes Physical World and Measurement CBSE class 11 Physics Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book. CBSE Key notes prepared by KVS and Delhi Schools. 




 Key Notes Kinematics
Key Notes Kinematics CBSE class 11 Physics Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book. CBSE Key notes prepared by KVS and Delhi Schools. 




Key Notes Law of Motion
Key Notes Law of Motion CBSE class 11 Physics Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book. CBSE Key notes prepared by KVS and Delhi Schools. 




Key Notes Work Energy Power
Key Notes Work Energy Power CBSE class 11 Physics Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book. CBSE Key notes prepared by KVS and Delhi Schools.



Key Notes Motion of System of Particles and Rigid Body
Key Notes Motion of System of Particles and Rigid Body CBSE class 11 Physics Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book. CBSE Key notes prepared by KVS and Delhi Schools. 




Key Notes Gravitation
Key Notes Gravitation CBSE class 11 Physics Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book. CBSE Key notes prepared by KVS and Delhi Schools. 




Key Notes Properties of Bulk Matter
Key Notes Properties of Bulk Matter CBSE class 11 Physics Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book. CBSE Key notes prepared by KVS and Delhi Schools. 



 Key Notes Thermodynamics
Key Notes Thermodynamics CBSE class 11 Physics Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book. CBSE Key notes prepared by KVS and Delhi Schools. 




 Key Notes Behaviour of Perfect Gas and Kinetic Theory of Gases
Key Notes Behaviour of Perfect Gas and Kinetic Theory of Gases CBSE class 11 Physics Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book. CBSE Key notes prepared by KVS and Delhi Schools.




Key Notes Oscillations and Waves
Key Notes Oscillations and Waves CBSE class 11 Physics Key notes and summary of the chapter with examples. These are very useful summary notes with neatly explained examples for best revision of the book. CBSE Key notes prepared by KVS and Delhi Schools. 



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