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Navneet Singh • 387 Reads

Chemical Bonding and Shape of Molecules

Molecular shapes

..S̘͖͚̱͈̟̖̣ͩͨ̅͑̑͋͆a̸̢̙̙̗̬̳̳ͩͥͨ̔͋m̸̖̼̹̦͍̙͕̝̬̭̳͠ͅi̥̦͉̟͖͙̪̳͎̟̜̳͎ͪ̽ͣ̉̾̋ͥ̎́̐ͫ̌͘͟r̸̙̥̜̺̼̱̩͍͉͙͕̍̐ͮ̏̒.. • 1159 Reads

Electronic Theory of Valency and Bonding

INTRODUCTIONElectronic theory of valency was given by Gilbert N. Lewis and Walther Kossel. This theory of valency explains the main cause of chemical combination and combining capacity of different elements on the basis of number of electrons present in the outermost orbit and tendency to lose or gain the electron. The terms ...

Temporary

ɐʇoʞdɐS ʇɐɹᴉq • 220 Reads

ALKANES : PROPERTIES

            PHYSICAL PROPERTIES OF ALKANES1) STATE: C1 - C4 = GAS                    C5 - C17 = COLOURLESS VOLATILE LIQUIDS                    C18 - ABOVE = WAXY SOLIDS2) ODOUR : ODOURLESS3) COLOR : COLORLESS4) SOLUBILITY : SOLUBLE IN NON-POLAR SOLVENTS                               INSOLUBLE IN POLAR SOLVENTS5) BOILING POIN...

Alkane

Bikash Agrawal • 214 Reads

Octane Number

Gasoline is used as a fuel in internal combustion engines of motor cars and airplanes. In such engines, a mixture of gasoline vapors and the air is compressed by a piston within the cylinder of the engine and the compressed mixture is ignited by a spark from the spark plug. As the compressed fuel-air mixture burns, considerab...

Difference between octane number and cetane number

Cyrus Roy • 212 Reads

Collision Theory: For a Layman

Before understanding about collision theory, we need to learn as to how chemical reactions take place. We know that for a chemical change to occur, the breaking of pre-existing bonds and the formation of new bonds is required. It is sure that the breaking of bonds should take place by the collision of molecules. The theory di...

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Navneet Singh • 201 Reads

Aliphatic Amines and their Preparation

Amines

Navneet Singh • 163 Reads

Aniline: Properties

Aniline

Bipin Karki • 262 Reads

Definition and Characteristics of Hybridization

Definition.Hybridization simply is the intermixing of atomic orbitals.In other words, the process of mixing of orbitals of an atom of nearly equal energy giving rise to entirely new orbitals equal to in number to the mixing orbitals and having identical shape and same energy is called hybridization.Characteristics.The number ...

Hybridization

Bishesh Gautam • 477 Reads

IUPAC Naming : Naming of Aromatic compounds

Compounds presence benzene structures rings pi electrons

Raunak Kumar • 203 Reads

Halogenation of Alkanes

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  1. What is the difference between a simple cell and a galvanic cell?

    Sorry for my late response. I didn't used the mattrab for a week long due to practical exam.

    Simple cell is usually referred to as a cell from which chemical reaction is carried out by the help of electricity.It is also know as electrolytic cell

    Where as in galvanic cell, electricity is generated out of chemical reaction(i.e. redox reaction).Galvanic cell is also know as electrochemical cell.

  2. Define secondary standard solution with suitable examples.

    Those solutions which are standardized by the titration with the primary standard solution are called a secondary standard solution.

    The examples of the secondary standard solution are:

    1. Decinormal H2SO4 solution
    2. Normal NaOH solution

  3. Describe the preparation and purification of pure and dry chloroform in the laboratory.
    Give its action upon:

    1. heated silver.
    2. aq. KOH
    3. aniline in the presence of aq. NaOH

  4. Mention the condition of precipitation in terms of solubility product and ionic product.

    When, Ionic Product > Solubility product, precipitation occurs.

  5. What is Riemann's green?

    Riemann's green is a green pigment ZnO.CoO, which is obtained by heating a mixture of zinc oxide and cobalt nitrate or by the reaction of cobalt nitrate with either  or zinc sulphate.

  6. Why is sigma bond stronger than pi bond?

    Sigma bond is formed due to the overlapping of orbitals along their intermolecular axis. This leads to the effective overlapping and high electron density along intermolecular axis.

    On the other hand, a pi bond is formed due to the sideways overlapping of orbitals. This side-ways overlap is partial and results in low electron density in intermolecular axis.

    This is why, a sigma bond is stronger than pi bond.

  7. Define the terms system and surroundings.

  8. pH of water at 24°c is 7. What effect does increase in temperature results in pH of water?

    1)pH will be more than 7

    2) pH will be less than 7

    3) pH will be equal to 7

    4) can't be determined

    Option 2 is correct ans .

    Dissociation of water is an endothermic  reversible reaction.

    When temperature is increased , for an endothermic reaction in equilibrium , it shifts the equilibrium to forward direction i.e. more product is formed which in this case means : more water is dissociated ( more H+  concentration ) is obtained . Ph= negative logarithm of H+ concentration so, more H+ concentration means, lesser Ph. so , whole ph range gets changed when temperature is increased i.e at that time, our neutral point is lesser than 7 but, still water is neutral !