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Solar System

Friday, February 24, 2017 / No Comments
In this video tutorial we have discussed the solar system with graphical representation of planatory position of each planets and sun.It will be helpful for students who are preparing for SSC Railway UPSC HSSC SCRA Banking and many other competitive exams. It is specially for the exams like CGLE CHSLE MTS.

If you want the notes solar system in PDF FORMAT comment your email address in comments below it will be delivered to you as soon as possible or subscribe our YouTube channel to get it.

Indus Valley Civilization Very Important Questions

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 In this video tutorial we have discussed very important Questions on Indus Valley Civilization/Harappa civilization that can be asked in any competitive exams like CGLE CHSLE MTS PO Clerk NTPC Civil services IAS conducted by SSC, Railway, UPSC, HSSC SCRA etc.
If you want these questions with answers in PDF FORMAT, We will mail it to you as soon as possible, so comment your email address in comments below.

Vocabulary For SSC,,Railway and Banking

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In this video tutorial we have discussed most important vocabulary words asked in previous 10 years ssc cgle exams and that can be asked in any competitive exam like CGLE, CHSLE, MTS, PO, Clerk, Civil services etc.
If you want these vocabulary words with meaning in PDF format than comment your email address below We will mail it to you as soon as possible.

Indus Valley Civilization

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In this video tutorial we discussed Indus Valley Civilization topic of history for various competitive exams conducted by SSC, Railway,UPPSC,UPSC,HSSC etc. This video is helpful for the exams like CGLE CHSLE MTS PO Clerk Civil services IAS etc.

                   If you want the notes shown in the video in PDF format than comment below your email address.we will email it to you as soon as possible.

Why we add Sulfuric Acid for Preparation of Satandard Solution of Mohr's Salt

Thursday, February 23, 2017 / No Comments
For the preparation of standard solution of Mohr’s Salt during titration, it is necessary to add dilute Sulfuric Acid to prevent the Fe2+ ions of Mohr’s salt solution from undergoing oxidation to Fe3+ ions.

But here, Nitric Acid (HNO3) or Hydrochloric Acid (HCl) cannot be used.
Why We Cannot Add Nitric Acid?
Since Nitric Acid is very strong oxidizing agent so, the Fe2+ ions present in in Mohr’s salt solutions will be oxidized both by Potassium Permangnate(KMnO4) and Nitric Acid(HNO3), which will result in an error in determination of volume of volume of KMnO4 reacting with Mohr’s salt solution.
Why We Cannot Add Hydrochloric Acid?
Hydrochloric Acid (HCl) cannot be used in preparation of standard solution of Mohr’s Salt because Cl- ion  in HCl will be oxidized by Potassium Permangnate(KMnO4).

Ionic Bonding

Wednesday, November 18, 2015 / No Comments
Ionic bonds are formed when an electropositive element react with an electronegative element. The molecules formed due to ionic bond are polar in nature. Some examples are Sodium Chloride & Magnesium Chloride.

Properties of Ionic Molecules 


  1. Hardness: - Since nature of bonding in ionic compound is electropositive and extend in all directions, hence molecules formed by ionic bonding are very hard.
  2. Melting and Boiling Point: - Because ionic bond involves electrostatic force of attraction hence the molecule formed by ionic bond is strong and omnidirectional it involves the breaking of entire lattice, which requires higher energy. Hence melting and boiling point are high.
  3. Conductivity: - They have low electrical conductivity in solid state but are good conductors in molten state because free movement ions in molten state.
  4. Solubility: - Ionic compounds are often soluble in polar solvents such as water. This is due to polar bonding in ionic molecules.
  5. Reactivity: - Due to involvement of ions chemical reactivity of ionic compounds are generally higher.

Structure of Ionic Molecules

Ionic compounds are generally crystalline structure and it is found in solid state at room temperature. Let’s lookat the following picture:-
Structure of Ionic Bonds

Among the above three structures of a molecule having coordination number 3, ‘A’ is most stable as the ions involved are closely packed and the attractive forces very well counter the repulsive forces as the size of cation increases more number of anions are required to stabilize the ionic solid. So, the coordination number also increases therefore radius ratio is an important parameter to determine the structure of the ionic solid. But it suffers various assumptions like molecule is a perfect sphere but in real that is not possible.
Radius Ratio

                                     
A molecule with a lower radius ratio value indicates greater stability.
Nowadays a technic known as X-Ray Crystallography is used to determine the complete structure of ionic solid.

Energy Consideration

Lattice Energy:-

The amount of heat released when one mole of lattice is formed from its constituent gaseous ions is known as lattice energy.
                    OR
Amount of heat absorbed when one mole of lattice is broken to its constituent gaseous ions is known as lattice energy.
Lattice Energy Determination

Born-Haber Cycle

Lattice energy can be determined experimentally by Born Haber cycle, which is based on the Hess’s law of constant heat summation.
Hess’s Law- It states that the energy involved in a particular reaction is same irrespective of the reaction proceeds in one step or via several steps.
Let’s we consider a general reaction of an ionic compound formation:-                          
Born Haber Cycle
From Hess’s law
Hess Law of constant heat summation

Born Lande’s Equation

According to Born Lande’s equation minimum lattice energy is given as follows: -
Born Lande equation
A = Med lung Constant (sum of all geometric interactions)
Z+ & Z- = charges on cation and anion respectively
N0 = Avogadro number
r = Interionic distance
n = Compressibility Factor (Born Constant)

Born Lande’s equation states that lattice energy is directly proportional to product of the charges of cation and anion present in the ionic compound. While it is inversely proportional to interionic distances. For example you can see the change in lattice energy due to change in product of charges and also due to change in interionic distances in following examples.
Ionic molecules comparison

From table ‘A’ we can see that where interionic distance in Lithium Fluoride and Magnesium Oxide are almost same while product of charges is 4 times more in the case of magnesium oxide than Lithium Fluoride hence lattice energy is energy is also approximately 4 fold in the case of MgO. This follows Born Lande’s equation which states that lattice energy is directly proportional to product of charges.
From table ‘B’ we can see that interionic distance is almost four times more in CsI than LiF and hence lattice energy is half in CsI than LiF. This also proves Born Lande’s equation true which states that lattice energy is inversely proportional to interionic distances.                    

JEE Main 2016: Admit Card,Exam Pattern,Result

Thursday, October 29, 2015 / 1 Comment
JEE Main
JEE Main is an entrance exam conducted by CBSE for admission in to various BE and BTech cources of India's premier institutes such as NITs, IIITs and other Government Funded Technical Institutions including Birla Institute of Technology. Every year around 13 lacs students appear for the exam.While there are 35-40 thousand seats available.So tight your belts to face such a competetive exam.This is also said to be screening test for JEE Advanced which is conducted for admission in to BTech cources of IITs.

How To Apply

There will be only one mode available to apply for the examination and that will be online. You have to first register on the Official Website of JEE Main and then you can fill the online form by logging in to your account. You have to keep your mobile number and an Email ID ready before applying. You should also have your picture in .jpg format and a scanned image of your signatre and thumbprint both also in .jpg format (For boys thumb print should be of left thumb while for girls it should be of right thumb).After filling online application you have to pay application fee. You have three mode to pay your application fee i.e. 
  • Internet Banking, 
  • using Debit/Credit Card and 
  • e-challan. 
Fee details are given below.

Application Fees

JEE Main Syllabus

Correction in Application Form

There will be given a 2 week period after filling online application to correct your mistyped details. Here you should keep in mind rhat you can not change the pattern of exam. So we carefull during the selection of mode of examination i.e. Online/Offline.

Admit Card

Admit card of the exam will be available in the month of March 2016. You can download it from JEE Main website.After downloading admit card you should immediately check details on it. If any discrepencies found quickly contact JEE Main authorities and get it corrected.

Exam Pattern

There are two modes of examination:-

  1. Paper Based Examination(Offline)
  2. Computer Based Examination(Online)
Carefully chose the type of your examination because it can nake or brake your dreams. If you are not given computer based examination earlier than you should never choose this option.But if you comfortable with online mode than you should definately go with it.
The exam will be of 90 questions(30 questions each from Physics, chemistry and maths)of 360 marks.All questions are assigned 4 marks.

Syllabus Of The Examination

You can download JEE Main Syllabus below.Download

Date Of Examination

Exam will be conducted in the first and second week of April 2016.(Expectation)

Result

Result of JEE Main will be declared in the end of April or first week of May 2016(Expected as previous years).

Preparation of All India Rank

After declration of result the All India Rank will be prepared in the end of May or in the first week of June 2016 (This can change because of below given reasons)It is expected that from JEE Main the All India rank will be prepared on the basis of marks obtained by the candidates in the entrance test.Previously it was prepared by giving 40% weightage to 10+2 marks and 60% to the entrance test marks.Now it wil be get scraped if Ministry of Human Resource Department of central government accepts it.The main reason behind scraping the inclusion of 40% board marks is delayed All India Rank preparation and late admission previous year.HOD minister Mrs.Smriti Irani had made a committi of NIT officials to investigate the matter and submit a report.According to reports it supports the scrapping of inclusion of board marks.While some other professors supports current system by saying that it increased the number of girls admission in previous years.Now Mrs. Smriti Irani has made another committie to solve the problem. made If it will be scrapped than it will benefits those students whose board marks are low but he scores well in the entrance exam.[update title="Update@Mesomers" icon="info-circle"]Date-08 November 2015
The HRD ministry has received the recommendations from the Committee of Eminent Person headed by Prof Ashok Mishra that government should abolish the addition of 10+2 board marks from JEE Main 2016 and it also suggested that number of students should be increased from 1,50,000 to 2,00,000 to be eligible for JEE Advanced fom this year.
Othe major recommendations are made that there is a new testing pattern will be launched from  the year 2017 called as National Testing Service which will take aptitude test of students which will be held online twice or thrice in a year. On the basis of performance in this aptitude test 4,00,000 students will be selected for JEE (a common exam for IIT,NIT,IIIT and CFTIs) conducted by IITs. and on the basis of that 40,000+ students will be selected for the admissions in IITs,NITs,IIITs and CFTIs through a common councelling process.  [/update]

Admission Process

It can start in the end of June or  in the first week of July 2016.But admission shedule can not be said appropriately because if 40% weightage will not be scraped than it may take longer in admission processes.

Previous Years Question Papers