Ncert Solutions Chemistry Class 12th
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New answer posted
10 months agoContributor-Level 10
8.3 Manganese (Z = 25) exhibits the largest number of oxidation states. This is because its electronic configuration is 3d54s2.
Because it has the maximum number of electrons (5 d electrons and 2s electrons) to easily lose and share.
Therefore, it can exhibit an oxidation state of +2 to +7. The compounds are as follows:
Mn (0) as Mn (s), Mn (II) as MnO, Mn (II, III), Mn etc.
New answer posted
10 months agoContributor-Level 10
5.22
Colloidal solutions get classified in 8 Types on the basis of physical state of the dispersed phase and dispersion This are given in following table-
Dispersed phase | Dispersion media | Types of colloids | Example |
Solid | Solid Sol | Gem stone | |
Solid | Liquid | sol | Paints, cell fluid. |
Solid | Gas | Aerosol | Dust, smoke. |
Liquid | Solid | Gel | Butter, Cheese. |
Liquid | Emulsion | Milk, Hair cream. | |
Liquid | Gas | Aerosol | Fog, Mist, Cloud. |
Gas | Solid | Solid Sol | Pumice stone. |
Gas | Liquid | Foam | Froth, soap lather. |
2) Depending upon nature of Particles of dispersed phase it can be classified into 3 categories
Multimolecular Colloids-In this colloidal particle consist of aggregates of atoms having diameter less than
Macromolecular colloids-The colloids in which Large particle aggregates and dissolved into suitable
Associated colloids – This colloids show Colloidal property at higher This contains ions of colloidal size.
3) Depending upon interactions between dispersed phase and dispersion medi
New answer posted
10 months agoContributor-Level 10
8.2 The enthalpy of atomization depends on the strength of the metallic bonding. Stronger the metallic bonding, greater is the enthalpy of atomization. The metallic bonding is strong when there are more unpaired electrons in the atom.
All transition metals (except Zn, electronic configuration: [Kr] 3d10 4s2), have at least one unpaired electron that is responsible for their stronger metallic bonding. Since the Zn atom does not have an unpaired electron, the metallic bonding is weak and hence the enthalpy of atomization is low.
New answer posted
10 months agoContributor-Level 10
5.21
Enzymes are complex nitrogenous organic compounds which are produced by Living plants and animals. They are protein molecules of higher molecular masses. They are effective catalysts termed as “biochemical catalysts”
Mechanism of enzyme catalysis- There are number of cavities present on the surface of colloidal particle of enzymes. They have specific shape and contains group like –COOH, -SH, - OH. etc. they are active centers of enzyme particle molecules of reactant which have complimentary shape fit into this cavities, this forms activated complex Which then decompose to yield products. This reaction occur in 2 steps-
Enzyme (
New answer posted
10 months agoContributor-Level 10
8.1 The elements which have partially filled d or f subshells in any common oxidation state are called as the transition elements. Silver (the Atomic number is 47 and electronic configuration is [Kr] 4d105s1) has a completely filled 4d orbital in its ground state but has two oxidation states (+1, +2).
In the +1 oxidation state, an electron is removed from the s-orbital and in +2 oxidation state, one electron from d-orbital is also removed. Thus, the d-orbital now becomes partially filed (4d9). Hence, it is a transition element.
New answer posted
10 months agoContributor-Level 10
5.20
Multimolecular colloids | Macromolecular colloids |
1) formed by aggregation of large number of atoms of smaller radii. | 1) Formed by particles of large size. |
2) Low molecular masses | 2) High molecular masses. |
3) Weak van there waals forces | 3) Strong van there waals Forces |
4) Ex-sols of gold and sulphur. | 4) Ex-Nylon, starch. |
Associated colloids- They formed by aggregation of large number of ions. instead of atoms or molecules in above two colloids. They have van there waals force directly proportional to concentration of ions. Ex- Soap Sol.
New answer posted
10 months agoContributor-Level 10
5.19
Lyophilic - lyophilic (liquid loving) this sols formed by direct mixing of substances like gum starch etc. with suitable liquid, called as lyophilic sols. This are called as reversible sol because if dispersion medium is separated from the dispersed phase it can be reconstructed just by mixing them. These sols are quite stable. Ex-Protein, Starch.
Lyophobic -lyophobic (liquid hating) this sols don't formed by direct mixing of dispersed phase and dispersion media they require special methods for preparation. Ex-Sols of metal sulphides .
This Lyophobic (Hydrophobic-water hating) sols gets easily coagulated because they are less s
New answer posted
10 months agoContributor-Level 10
5.18
Temperature- Adsorption decreases with increase of temperature because it is an exothermic process, by using le chatelier's principle the reaction will proceed in backward direction.
Pressure- Adsorption increase with increase in pressure at constant temperature.
New answer posted
10 months agoContributor-Level 10
5.17
Colloidal solutions get classified in 8 Types on the basis of physical state of the dispersed phase and dispersion medium. This are given in following table-
Dispersed phase | Dispersion media | Types of colloids | Example |
Solid | Solid Sol | Gem stone | |
Solid | Liquid | sol | Paints, cell fluid. |
Solid | Gas | Aerosol | Dust, smoke. |
Liquid | Solid | Gel | Butter, Cheese. |
Liquid | Emulsion | Milk, Hair cream. | |
Liquid | Gas | Aerosol | Fog, Mist, Cloud. |
Gas | Solid | Solid Sol | Pumice stone. |
Gas | Liquid | Foam | Froth, soap lather. |
New answer posted
10 months agoContributor-Level 10
5.16
When adsorbate (gas or liquid mostly) absorbed then their entropy get reduced i.e. ΔS is negative. For every spontaneous process ΔG must be negative. ΔG = ΔH - TΔS, as TΔS is positive (ΔS is negative) ΔH must be negative in order to make ΔG negative. Hence ΔH is negative that means the reaction is exothermic. Hence every adsorption reactions are exothermic.
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