Ionic strength – solved problems – AdiChemistry – IIT JAM JEE NEET

June 17, 2018

Quick video presentation on Ionic strength through solved problems – supplementary to Debye-Huckel’s theory.

https://youtu.be/U54DQz36-O4
You will find how solve following problems in above video.
1) Identify, from the following, the correct ionic strengths for (A) 0.01 molal solution of NaCl and (B) a 0.01 molal solution of Na2SO4. (CSIR NET JUNE 2013)
1) A) 0.010 mol kg-1 B) 0.010 mol kg-1 2) A) 0.010 mol kg-1 B) 0.025 mol kg-1
3) A) 0.010 mol kg-1 B) 0.030 mol kg-1 4) A) 0.010 mol kg-1 B) 0.015 mol kg-1
2) The ionic strength of a solution containing 0.008 M AlCl3 and 0.005 M KCl is:
(CSIR NET DEC 2016)
1) 0.134 M 2) 0.053 M 3) 0.106 M 4) 0.086 M
Also visit: http://www.adichemistry.com/
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Hybridization sp sp2 sp3 sp3d sp3d2

March 5, 2018

What is hybridization?

The intermixing of two or more pure atomic orbitals of an atom with almost same energy to give same number of identical and degenerate new type of orbitals is known as hybridization.

The new orbitals formed are also known as hybrid orbitals.

Almost always, some sort of intermixing i.e., hybridization of pure atomic orbitals is observed before the bond formation to confer maximum stability to the molecule. You can find selected illustrations of different types of hybridizations in the following sections.

JUMP TO EXAMPLES OF SP HYBRIDIZATION

JUMP TO EXAMPLES OF SP2 HYBRIDIZATION

JUMP TO EXAMPLES OF SP3 HYBRIDIZATION

Wilkinson’s catalyst – for CSIR NET GATE IIT JAM chemistry exams

October 2, 2017

RhCl(PPh3)3 – Chlorotris(triphenylphosphine)rhodium(I), is known as Wilkinson’s catalyst. It is used as a homogeneous hydrogenation catalyst. It is a square planar 16-electron complex. The oxidation state of Rhodium in it is +1.

wilkinson's catalyst structural formula

FIND MORE INFORMATION AT

http://www.adichemistry.com/inorganic/organometallic/catalysis/wilkinson/wilkinsons-catalyst.html

 

Indeed, Wilkinson’s catalyst is a pre-catalyst that is converted to an active form by losing one triphenylphosphine ligand before entering the catalytic cycle. Usually, the solvent molecule fills the vacant site.

Initially, the catalyst activates the molecular dihydrogen by oxidative addition mechanism to give a 18 valence electron dihydrido complex. The oxidation state of Rh is increased to +3. Thus formed dihydrido complex binds to the olefin in the next step with the concomitant loss of solvent or PPh3 ligand. Since the activation of dihydrogen occurs before addition of olefin, this path is referred to as dihydride path .

Now one of the hydrogen undergoes migratory insertion at the double bond. This is a slow step i.e., Rate Determining Step (RDS).

Immediately and finally, the alkane is released rapidly by an irreversible reductive elimination step that completes the catalytic cycle. The oxidation state of Rh is decreased to +1 and the catalyst is regenerated.

Physical Chemistry

April 13, 2017

Physical chemistry deals with the basic principles of physical science involved in chemical systems. It often deals with the macroscopic side of chemical systems; like inter molecular forces, thermodynamic properties, chemical equilibria, reaction kinetics and electrochemical processes.

However modern physical chemistry also deals with the principles of quantum mechanics to help in understanding the chemical phenomena at atomic and molecular level.

On the following page you can find links to topics in physical chemistry.

http://www.adichemistry.com/physical/physical-chemistry.html

 

IIT JEE 2015 solved question paper

October 21, 2016

Find step wise interactive solutions to: IIT JEE 2015 main in chemistry subject at: http://www.adichemistry.com/jee/free/paper/main/2015/index.html. It is also equally helpful to NEET aspirants.

 

Sample questions:

 

 

The ionic radii (in Å) of N3-, O2- and F are respectively:

(1) 1.36, 1.40 and 1.71
(2) 1.36, 1.71 and 1.40
(3) 1.71, 1.40 and 1.36
(4) 1.71, 1.36 and 1.40

 

The synthesis of alkyl fluorides is best accomplished by :

(1) Free radical fluorination
(2) Sandmeyer’s reaction
(3) Finkelstein reaction
(4) Swarts reaction

FACTORS AFFECTING RATE OF A CHEMICAL REACTION

August 22, 2016

Factors that influence the reaction rates of chemical reactions include :

1) Concentration of reactants

2) Pressure

3) Temperature

4) Catalyst

5) Nature of reactants

6) Orientation of reacting species

7) Surface area

8) Intensity of light

9) Nature of solvent

According to the collision theory, the rate of a reaction is directly proportional to the number of effective collisions per second between the reactant molecules. Rate of a reaction is directly proportional to the concentration of reactants.

i.e. rate (r) ∝ cn 

where

c = concentration

n = order of the reaction

or r = kc

where

k = specific rate

Explanation: The number of collisions and hence the activated collisions between the reactant molecules increase with increase in concentration. Therefore, according to the collision theory, the rate of a reaction should increase with increase in the concentration since the rate is directly proportional to the collision frequency.

 

MORE AT

http://www.adichemistry.com/physical/kinetics/factors/factors-affecting-rate-reaction.html

Interactive solutions to IIT JEE 2015 chemistry question paper

October 12, 2015

Are you afraid of IIT JEE chemistry paper? Do you want to score more marks in it easily? Just visit interactive solutions page for 2015 MAIN question paper at:

http://www.adichemistry.com/jee/free/paper/main/2015/index.html

It is a great way of learning concepts step by step. Use modern browsers like firfox or chrome to access the content.

BCC

CSIR NET & GATE chemistry study material & free online coaching

May 26, 2015

A great way to improve your score in CSIR NET & GATE exams is possible when you read selected topics along with one textbook from your area of interest. It is very simple and logical.

Adichemistry site is offering such an easy study material & free online coaching to make your life easy while attempting exams at this higher level.

Find more information at:

For study material: http://www.adichemistry.com/common/htmlfiles/csir-gate-chemistry.html

For free online coaching:

http://www.adichemistry.com/csir-net/chemistry/online-coaching.html

This is the best substitute for costly but ineffective offline coaching.

CSIR NET CHEMISTRY STUDY MATERIAL

October 30, 2014

Welcome. Good news to chemistry students, who have a strong desire to pursue their dream research with a scholarship at prestigious institutions of India. I launched this web page to cater the needs of aspirants who wish to crack CSIR NET &  GATE exams in chemical sciences.

On this page, you can find CSIR NET chemistry study material and solved previous year model papers, that help in preparation and makes your life easy.

For more information visit: http://www.adichemistry.com/common/htmlfiles/csir-gate-chemistry.html

Electrolysis – Electrolytic cell – Electrodes

May 17, 2014

ELECTROLYSIS

Electrolysis involves dissociation (lysis) of an electrolyte by using a direct electric current.  In this process, electrical energy is used to carryout a non-spontaneous redox chemical reaction.

The setup used to serve this purpose is known as electrolytic cell.

ELECTROLYTIC CELL

What is an electrolytic cell?

An electrolytic cell is used to perform electrolysis. It is provided with two electrodes, which are connected to different ends of the DC electric source. The electrode connected to the positive end is referred to as anode and that which is connected to the negative end is referred to as cathode.

http://www.adichemistry.com/physical/electrochemistry/electrolysis/electrolysis.html

electrolytic-cell