 Next compound is hydrogen peroxide. Hydrogen peroxide H2O2. Preparation from, from barium peroxide. Preparation from barium peroxide. Write down, hydrated barium peroxide, hydrated barium peroxide reacts with dilute S2SO4 to form hydrogen peroxide. This is the reaction. Once they ask this question, they don't use here and hydrous form of this we do not use. Barium peroxide and hydrous form we do not use. Write down the next line here. Hydrous barium peroxide forms a protective layer of barium sulphate. Hydrous barium peroxide forms a protective layer of barium sulphate on barium peroxide and hence the further reaction is not possible. Hydrous barium peroxide forms a protective layer of barium sulphate on barium peroxide and hence the further reaction is not possible. Sir, so barium sulphate is soluble in water? Yes, this forms, it gets dissolved and hence it won't accumulate on the surface. Let's write down the structure of this. The structure of H2O2 is open book structure. It is an open book structure and it is something like this. This is here. Oxygen has 2 lone pairs. The bond length is L1, this is L2 and this is L4. The bond angle here is 97 degrees. This is also 97 degrees. I think it is 97 degrees. See, how much means what? See, open book structure is this. Suppose this is the oxygen. Here we will have one oxygen and another oxygen is this. So this oxygen, this bond is 90 degrees but still the bond angle is 97 or 100 whatever you said. So this oxygen and hydrogen bond is something like this. It goes this way and this oxygen and hydrogen bond is like this. So this looks like open book. So this is an open book structure, non-planar structure. There is a non-planar structure. Write down non-planar. Which bond length is more here? L1 or L2? Why L1 is more? L2 is more than L2. Here we are repulsion. L1 is more than L2. It is a question they ask in the exam. L1 is around 1.48 and L2 is 0.97. Can you draw the orbital diagram of H2O2? Can you draw the orbital diagram of H2O2? Then it is oxygen-oxygen bond forms. What are the orbital overlaps here? Yes, draw the structures. This is hydrogen atom. This is sp3. This one is sp3. This one is also sp3. Okay, one last thing we will discuss here. Three different types of forms of hydrogen we have. First we will write down nescent hydrogen. Just you have to memorize this. Write it down fast. Hydrogen. Hydrogen now. At the moment of formation, at the moment of formation, don't add nescent hydrogen. It is more reactive than ordinary hydrogen. Generally forms at ordinary means normal temperature. Not at very high temperature. The most important property is it has less reducing power. The second one is atomic hydrogen. Atomic hydrogen, this forms at normal temperature, generally at lesser temperature. Atomic hydrogen forms at relatively higher temperature. So right now it forms at higher temperature. At lower temperature. When hydrogen gas passes through an electric arc, at that time it dissociates into its atomic form. That is atomic hydrogen. So for basic hydrogen, if you reduce the temperature of normal hydrogen, it is possible at a lower temperature. See, it is just one state. If you have nescent hydrogen, hydrogen is forming. Hydrogen forms and then it converts into atomic hydrogen. Just the moment where the atomic hydrogen is forming. Before that, only the state of hydrogen, whatever. Atomic hydrogen at high temperature. No, low temperature. Normal temperature basically. Comparatively here we have higher temperature. This forms when you have H2 gas, suppose hydrogen gas, it passes through an electric arc. Electric arc, higher temperature. This converts into atomic hydrogen. Atomic hydrogen. This has more reducing power than less. So what is the decent hydrogen? How is it? It is hydrogen only. Like apart from the temperature at which it starts. How wide does it have? It has very less intensity to lose electron. What? See, obviously it is just the game of temperature. So the higher temperature, hydrogen has more intensity to lose electron. Because temperature is high, the electron present in the orbital. It has more tendency to go out. But then, if it is just the temperature thing, it is not hydrogen's fault. So why are we classifying it as being significant enough for the reaction? See, it reduces the property. One of the properties reduces the property. It is different for the two hydrogen. But that is just the temperature. That is what. At one particular normal temperature, its property is different than this. Means the active hydrogen atom we have, its property is getting changed when you change the temperature. At different different states, we have defined the two different types of hydrogen. So based on temperature, the reactions they undergo also change? Obviously, because the electron, the tendency to release electron for mesent hydrogen is less than that of atomic hydrogen. So generally, a higher temperature required for mesent hydrogen is different. But for reaction, generally we take atomic hydrogen. Okay, so this is a relatively higher temperature. And it has more reducing power. More reducing power for atomic hydrogen. Once they have asked comparison of reducing nature of these two hydrogen. So reducing property, you must remember. The last one is, write down the last one. The third one is ortho and para-hydrogen. Ortho and para-hydrogen. Ortho and para-hydrogen. In the hydrogen molecule, both protons, two protons are there in the hydrogen molecule. So in both protons, it spins in the same direction. It spins in the same direction. Then it is known as ortho-hydrogen. So it says spin, spin. Proton rotates around its own axis. So if it is same direction, then it is ortho. If it is opposite direction, then para-hydrogen. Why does it rotate around its own axis? Protons always rotates around its axis. Yes, always rotates around its axis. So this is ortho. You find a way to rotate them. So with these electrons, they have to always evolve. Protons have to evolve. Yes, so exactly. So in the hydrogen molecule, it spins around its own axis. Is there one way to rotate a proton? Yes. This way, it rotates around its own axis. So this will rotate. This is a very light particle. It goes through a very small amount of energy it can move. Right. That's why it rotates around its axis. So same direction as ortho. Opposite. So ortho is, when proton spins the same, then when the spin of the proton is in opposite direction, it is called as para-hydrogen. Ordinary hydrogen has 75% ortho and 25% para. This is the observation factor. 25% ortho and 25% rest. This is the example. NCRT just go through few properties of hydrogen. You just have to go through NCRT.