State Board Commerce (XI-XII) - Test Papers
Importance of World International Literacy Day.
World Literacy Day- A World Ahead
“Education is not preparation for life; Education is life itself.” – John Dewey
With no boundaries or limitation, the only thing that can make you a diamond from coal is Education. There is nothing as powerful as education and we should celebrate the day to revise the goals of distributing this power.
Every year, the World Literacy Day is celebrated on September 8. This year, UNESCO is celebrating the 51tst anniversary of International Literacy Day with the quote “Reading the Past, Writing the Future”. This day was is celebrated all around the world to spread awareness about the importance of the literacy to individuals, society, and communities.
UNESCO Director-General Irina Bokova said, “The world has changed since 1966, but our determination to offer every woman and man with the capacities, skills, and opportunities to become everything they wish, in respect and dignity, remains as firm as ever. Literacy is a foundation to build a more sustainable future for all.”
As per the report of the global monitoring, it has been observed that one among every 5 men and two third women are illiterate. Hence, to increase the literacy rate World Literacy Day is celebrated.
Why We Celebrate International Literacy Day-
The main purpose to celebrate the International Literacy Day is to encourage awareness towards literacy so that everyone can know their social and individual rights. As we need food to be live, we need literacy for social and personal development. Considering the immensely increased rate of poverty, uncontrollable population growth, gender inequality, etc. UNESCO has decided to celebrate the day with a goal to remove these problems. Eliminating them not only helps individuals to grow, but also contributes to the overall growth and upliftment of the nation.
Why Literacy is Important-
Literacy is not only the way to get employment however, it encourages to know human rights so that everyone can get what they deserve. Due to illiteracy, many people face humiliation every day. Moreover, they make their own life full of struggles. Hence, to make a better world and to make use of community resources for gaining information from local and school libraries, literacy is of utmost important.
In the mission to spread literacy around the globe, Robomate+ has taken an initiative. It is the India’s largest video platform that provides easy to understand and interactive video lectures. No matter which class or exam you are preparing for, video lectures on almost every concept are available at Robomate+.
So let’s pledge on this literacy day, we learn, we teach, we inspire, to make our future full of knowledge and success
NEET & AIIMS 12th PCB-Chemistry-Solution and Colligative Properties 2 Demo videos
Hello, dear students, we are studying the chapter, Solution and Colligative Properties, so in this module let me take you through the understanding of vapour pressure versus the temperature, so let us go with that.
Now we will see the distribution of molecular speeds in liquid, as I said that it has similarities to that of gases, so let’s see that first. Well, liquid also has the random motion like gases as well as their distribution is similar to that of velocity distribution of gases. So we have learnt that in earlier modules also. So, and we learnt that this is because of the Maxwell-Boltzmann’s Distribution which is nothing but a plot between a number of molecules versus the kinetic energy. So if we plot that let us see what I can see here, number of molecules versus kinetic energy. Now at a certain temperature T1, this is how the graph varies, this was a similar graph for gases also. Similarly, if at all I increase the temperature, let me take it to T2 temperature, then the graph will vary in this way, that is it will slowly peak will start coming down and it will start becoming more uniform. So in that case now what I could suggest here is let us take a point or kinetic energy after which let’s say liquid particles are starting to escape, right, so this is the kinetic energy, what you can call is the minimum kinetic energy required for molecules to escape from the liquid state. So that is what it is, so it is the minimum kinetic energy. Now if this minimum kinetic energy if at all being drawn towards that curve they will start touching at two different points, then they will generate an area under the curve. So let us see what exactly it represents, so at temperature T1, area under the curve represents the number of particles which are escaping out to the vapour phase. So that yellow coloured is the area which shows that at temperature T1 how many number of particles have escaped. Similarly at temperature T2 you could see this blue coloured shaded part as well as the yellow coloured part, both of them combined are the total number of particles escaping out to the vapour state. So it is very clear that in vapour phase molecules are more at higher temperature, right, as we learnt this earlier also, as the temperature is increased vapour pressure will also increase, right. So what does that mean, you can see evidently here that at temperature T1 the number of molecules escaping are very less but at temperature T2, you could see number of particles escaping are more. So therefore what I could conclude here is low temperature is equivalent to say that it is less likely to vaporize that means it is low vapour pressure. While high temperature it is equivalent to say more likely to vaporize therefore it is at high vapour pressure. So you can now relate how vapour pressure and temperature are co-related to each other, right. So let us try to derive that, now we know that vapour pressure will only be defined when liquid-vapour equilibrium is existing so therefore let me consider that liquid vapour equilibrium is there where K1 is the equilibrium constant and P1 is the vapour pressure. Now therefore K1 is the equilibrium constant at temperature T1 and P1 is the vapour pressure of liquid at temperature at T2.
Now what I can say according to Vant Hoff’s equation we can always relate that as log of K2 by K1 is equal to delta H vaporization by 2.303R into 1 by T1 minus 1 by T2. This is Vant Hoff’s equation where Delta H vaporization is the enthalpy of vaporization, right.
Now observe it carefully, can we write K1 is equal to P1, because yes, liquid does not have any vapour content so therefore vapour phase as P1 so equilibrium constant K1 will be equal to P1. Similarly, if at temperature T2 I can write K2 is equal to P2. So can I change that log of K2 by K1 as P2 by P1. So in that case this Vant Hoff’s equation will be converted to Clausius-Clapeyron’s Equation. So, students, that is how we derive at Clausius-Calpeyron’s equation which is the relation between the vapour pressure of the liquid versus the temperature for a volatile solvent.
So as we go into the next module we will see its applications and more importantly how it will derive towards the Rour’s Law.
Thank you.
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NEET & AIIMS 12th PCB-Chemistry-Solution and Colligative Properties 1 Demo Videos
Hello, dear friends, we are studying the chapter, Solution and Colligative Properties. So in this module I will take you through the next colligative property which is elevation in boiling point, so let us see that.
So when I say elevation in boiling point, the first thing we need to know is what is boiling point. It is the temperature at which the vapour pressure of the liquid becomes equal to the external pressure. So that is what is boiling point.
Next, on addition of a non volatile solute the vapour pressure of the solvent will always decrease. That is what we learnt from the colligative properties definition itself earlier and which is in fact giving us the first one which is relative lowering of vapour pressure, right.
So, next thing, therefore to boil the solution, the required temperature will always be higher so it will take more amount of temperature or more amount of energy to boil the same solution. So let me show you this more graphically, instead of reading it out more like a point wise, let me show you the same thing graphically here. So we know that at boiling point vapour pressure of the solution will be equal to external pressure so taking that into consideration let us start with the graph here.
So, let me draw the graph between vapour pressure versus temperature, right. So now closely observe the vapour pressure line, I have drawn a line here which is the P external that is 1 Atm. Now for volatile solvent at equilibrium we know that solvent and solvent which is at liquid and which is at vapour, there is always an equilibrium established and we can use Clausius-Clapeyron Equation which is lnP is equal to delta H vap by RT. So therefore lnP versus T you can see how it is going to be. It is more like a logarithmic graph versus 1 by T. So, if at all I draw that between vapour pressure and T, the graph will look something like this. So this is that solvent graph, got it. So using that equation which we just mentioned.
Now observe it very carefully, if at all I draw this particular line and it hits at that point X axis and that point Tb0 is the boiling point of the solvent. And as I said earlier the first point, so vapour pressure of the liquid has just become equal to external pressure and that’s why it is called the boiling point.
Now, the next point is now on adding the non volatile solute I told you that the vapour pressure will decrease. Now if the vapour pressure will decrease we learnt this earlier the curve was supposed to shift onto this side, so now the curve will look more like this for solution, got it. Now observe again carefully, if at all I draw this line it will touch at Tb. Now this is a temperature which is higher, right. So to reach that 1 Atm which is the external pressure I am requiring more temperature here. So the temperature will be higher, so that is what I said. Now there is a certain difference which is established and that difference, delta Tb is what is the elevation in the boiling point, and therefore this point becomes the boiling point of solution. So to reach that 1 Atm, so we need Tb. So what I can conclude here that Delta Tb is equal to Tb minus Tb0 and that is what we call it as the elevation in boiling point.
So we will see how we can write it in the mathematical way. So elevation in the boiling point is directly related to molality, so I can write delta Tb is directly proportional to molality and molality will always have the unit of mol per kg. So therefore I can write delta Tb is equal to some constant Kb into m. And this constant Kb is called Ebullioscopic constant or Molal Elevation constant. Please remember very, very important constant using problem solving, got it.
So now, m depends upon number of mols of solute particles, that is more the number of solute higher will be the elevation in the boiling point, right, because it is directly related. So therefore, if m is equal to 1 I can say delta Tb will be equal to Kb. And units of Kb will be Kb is equal to delta Tb by m, so therefore unit will be Kelvin kg per mol or degree centigrade kg per mol. So units are also very important, students, so please remember that carefully, it is Kelvin kg per mol.
And Kb for water usually it is always given in the problems but still it is better to remember, it is 0.52 Kelvin kg per mol.
Now, let me take you ahead in determining Kb and this can be derived from enthalpy and boiling point. Now in this equation delta Tb is equal to Kb into m. We know that m is responsible for the property of solute, while Kb will be responsible for the property of the pure solvent. So that means Kb is all related with the solvent properties. So therefore, Kb is given as R Tb square M by delta H vap. What is this Tb, M and delta H vap, well these are all values for the solvent only. So what are those, let me write down that.
So R is the gas constant, we always take it as 8.314 joules per mol per Kelvin.
Tb is the boiling point temperature in Kelvin.
M is the molar mass in kg per mol.
Again please remember we have to write that in kg per mol and this is for solvent, not for solution.
And then delta H vaporization which is the enthalpy of vaporization in joules per mol or cal per mol as per whatever be the values of Kb.
So this is how we have to calculate Kb.
Kb can also be represented in another form which is R Tb square by 1000 into Lv. Now what is this Lv, we know that R is gas constant, Tb is boiling point, M is molar mass, but Lv is the latent heat of vaporization which is usually represented in joules per gram. So either the question might give you delta H vaporization or Lv. Using any of these we have to calculate Kb and accordingly we have to go for further applications.
As we go for the next modules we will see the applications of elevation in boiling point.
Thank you.
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NEET & AIIMS 12th PCB-Chemistry-General Organic Chemistry Demo Videos
Hello, students, in the previous module we talked about the flipping of the chair conformation and I told you that there are going to be several more conformations those comes in between these two extreme chair conformation.
So, let’s actually study the conformational analysis of Cyclohexane. So, what are those several more conformations that we get during the process of flipping. So, this is nothing but a chair conformation and in the process of flipping the rotation of the carbon, carbon sigma bond first convert that into one of the momentary arrangement like this called as half chair conformation. The further rotation triggers the flipping of the bonds and converts this half chair into this kind of conformation called a twist boat. Where this twist boat on further rotation gets converted to a boat conformation and this boat further gets converted into new conformation which is again like a twist boat just like a mirror image of c. Whereas this twist boat further gets converted to a half chair conformation and ultimately this half chair conformation gets converted to the other extreme end of a chair conformation.
Well, if we study the energy changes taking place during the flipping of the chair conformation the graphical representation that we get and what you simply call as the conformational analysis of Cyclohexane. So, let’s learn it actually the chair conformation. So, this is the graphical representation as we have studied earlier the chair conformation of the Cyclohexane is the most stable hence least energetic. Well, in the process when the flipping starts this (a) form that is chair conformation gets converted to the next one which is nothing but half chair, where this half chair and the chair conformation are separated by the energy barrier of 10 kilo calorie. This half chair in a flipping further gets converted to, that is (c) one which is nothing but a twist boat and this twist boat is higher in energy as compared to chair conformation by 5.5 kilo calorie. Well, further flipping pushes this twist boat into the new conformation that is the boat conformation. Well, this boat conformation is again important for us with the examination point of view. But one information that we need to know this boat conformation is separated by the energy barrier in comparison to a chair conformation by 6.9 kilo calorie. Why such a large difference in the energy between the chair and the boat. Let’s look at this, in this boat conformation if you observe these 8 hydrogen atoms which are highlighted. These 8 hydrogen atoms come exactly behind each other if you observe them in the Newman projection, which means due to the eclipsing of these bonds this boat conformation exhibits a torsional strain and not only that if you observe this two H’s now, which is pointing towards each other they start creating a steric strain. And since they look like a pole it is sometime also called as a Flagpole interaction. Due to presence of the steric strain and the torsional strain this boat conformation is having 6.9 kilo calorie higher than the chair conformation. Well, this boat as we have seen earlier then gets converted again to a twist boat and this twist boat in a flipping process further gets converted to a half chair and ultimately we get the extreme end, that is nothing but a chair conformation.
So, this analysis gives us clarification about what are the various conformations that we get in a process of a flipping of a chair conformation.
That’s it from this module. Thank you so much.
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Tips and Strategy for Group Discussion
Group Discussions (GDs) provide organisations and B-Schools with a simulated managerial setting in which the candidates can be assessed. The selectors find it the quickest method to assess 12 to 14 candidates in the span of mere 20 minutes or so. This makes GDs a convenient personality assessment tool in the selection process, though some of the top B-schools have recently substituted group discussion with an extempore essay writing.
The first thing about a GD that candidates must remember is that they are under constant observation. Every word, gesture, conscious or unconscious move and expression of the candidate provides certain clues about the personality of the candidate. These clues are then reduced to data that help the panel assign an appropriate ranking or marks to the candidate. It hence becomes necessary to maintain decorum, a formal yet friendly attitude, and an air of involvement throughout the group discussion.
Content
The two broad parameters that are applied to the observation of a candidate are the ideas expressed by a candidate – the content – and they way in which those ideas were communicated to the group – the process. These are then assessed in real time to make certain reasoned judgments about the candidate.
Candidates are generally wary about the quality of content that they can bring to a GD, as the topic can be something that they are hardly familiar with. This is all the more so in topics that are termed as ‘abstract’ – giving no clue about what is actually meant by the topic, or what is expected from the candidate. However, generating content in a GD is not an impossible task for an acute thinker. Any topic, even the one based on current affairs can be looked at from various angles of human interest in order to generate sufficient content to speak for a minute or so at one time and five or six times in a GD. All GD topics definitely carry sufficient relevance to broad issues of human interest – economic, historical, social, psychological, and moral. Hence what one speaks not only reflects one’s background reading and thinking, but also one’s resourcefulness, ability to think on one’s feet, one’s analytical skills and, to a keen observer, one’s value system. A candidate has to project an image of confidence, maturity, and intelligence. Hence the content that one generates in a GD speaks volumes about several aspects of a candidate’s personality.
Presentation
Though the second broad parameter about ‘the process’ is not so worrisome to candidates, the way one speaks in a GD is of paramount importance – or at least as important as the content itself. The way one is willing to listen to another, the dignified manner in which one corrects a wrong or incomplete perception or point of view, the humility one shows in accepting reasons more valid than one’s own, the eagerness to learn from another, the keen interest one has in the deeper issues of human interest that the analysis has thrown up, and a mind that is ever open to new ideas are all mirrored by the way one participates in a GD. The process is the true gauge of interpersonal skills.
Leadership skills
A much discussed and rather glorified aspect of a group discussion is about ‘leadership skills’. Many youngster go astray in GDs because of their rigid and erroneous notions about leadership skills. What do leadership skills really mean in the context of a GD? Leaders are confident, are steadfast to their ideologies and vision – in that respect may even be termed as ‘obstinate’, are unwilling to compromise, and are able to convert willing listeners to his or her point of view etc. etc. In the context of a group discussion all these traits seem to be almost counter-productive in group activities. And they are so. Leadership skills in the context of a GD are completely different form the qualities described above. In the corporate world, and management education, it is situational leadership that is far more important. Situational leadership includes the ability to take the team to a win-win situation by perceiving and analysing the strengths and the weaknesses of the team, and by being one with the team.
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NEET & AIIMS 12th PCB- Biology-Microbes in Human welfare Demo Videos
Hello, students, welcome to this new chapter and that’s Microbes in Human Welfare. Well, in this module we are just learning the introductory part of this chapter. Well, students, I said microbes in human welfare. Don’t you think it means that somewhere or somehow we human beings are dependent on these microbes. So, let’s study this.
Now, these microbes are everywhere, then why can’t we see them with our naked eyes? It’s because they are very small. So, they are even smaller than these 0.1 mm. So, they are approx 0.1 mm or even less than that in size. Well these microbes are present in different morphology or say different types. So, we will study them, what are these different morphologies of these micro-organisms? So, we found them in the form of bacteria, fungi, protozoa and these microscopic plants and they are also found in the form of viruses, viroids, prions. So, these are the different morphologies of these micro-organisms which are found in tiny, tiny sizes around us. Well, nowadays with the recent technologies we have started growing these micro-organisms in our lab. Well, yes, now let’s see this beautiful picture we can see that how a person is holding this petri plate where you can see there are certain nutrient media. Now this nutrient is what is required for the growth of these micro-organisms. Well, here you can see certain colonies, all these circular things, these are colonies of all different types of microbes and we have grown them here in this petri plate and it is really looking beautiful. Well, as I already told you these micro-organisms are present everywhere. So, let’s see a few examples.
Yes, they are present in soil around us; they are present in even in dead wood, wow. Mud, say be it food products, air, water, clothes, nails, skin, jams that becomes the part of food products. They are also found in other organisms. Now, what does it mean? Yes, they are also present inside us, in our body and that’s how they are widely across, surrounding us and also in us. So, that’s really an amazing part. In fact, wait, they are also found in the extreme environments. Now, what does this mean, guys, extreme environment? Let’s see, so here comes microbes, well, they are also found in space, that’s really wonderful. They are also found in Antarctica. And we know Antarctica, there is snow, snow, snow. Well, they are also found in highly acidic environment and that’s really amazing. And yes, they are found at 100 degrees Celsius in fact even they are found at more than temperature of this. Now, and this we already know, right, they are also found under the snow. Say, under the layers of snow because we already know they are found in Antarctica. So, just imagine how widely and widespread these microbes, tiny, tiny microbes are, well, that’s really beautiful to know.
Well, if they are so widely found across us and they are so widely spread in our biosphere and as we have known them more for being harmful and pathogenic, how do we survive, how do we exist so conveniently? It’s, of course, because we have certain good micro-organisms too in our biosphere. Now, what does it mean good microbes? If I say good microbes, it means that we might be getting some use or some application of these micro-organisms in our day to day life, yes, exactly. So, these good microbes are actually helping us out in lot many activities in our day to day life.
So, here we are going to see one by one all the uses of these micro-organisms in our day to day life. So, here comes the first use and that’s microbes in household production and that’s really wonderful use, students. You might be, you might be eating curds, sometimes yoghurts, jams, right, butter. All these are somewhere getting worked upon by certain microbes. So, that’s how wonderful role they have even in our day to day, even in our kitchen. Here comes the second use of microbes and that’s microbes in industrial productions. Students, that is really wonderful use because, now what kind of things we produce in industry using these microbes. Yes, we are producing antibiotics, vitamins. Now, you can just imagine what important use we have of these microbes, yes. Now, let’s see the third use and that’s really again a blessing to us and that’s how we can reuse this sludge water, in fact, and that is microbes in sewage treatment plant. So, that’s, I agree with you, it’s really a very important use of these microbes. Now, here comes the fourth use and that is microbes in biogas production. Now, again it is a blessing, students, because of these microbes we have got an alternative source of fuel. So, that’s really a wonderful use of these microbes. Well, here comes the fifth use and again it is a curing for us, for our crops, for our farming and for our agriculture. And that’s microbes as bio control agents. So, that’s really a wonderful use again. And here comes the last but not the least and that is microbes as bio fertilizers. Now, you might have heard of organic farming, right. Yes, exactly there comes the role of microbes as bio fertilizers.
So, you just saw how important, how crucial role these microbes are playing in our day to day life. So, that’s really lot of important uses we just saw.
Now, students, in this module we just saw the introductory uses. Well, in the further modules we are going to learn all these use in detail one by one. Well, for listening thank you, take care.
