The experiment was not only of great practical significance, but also an excellent educational opportunity, so in addition to the participants Agatha, Sylvie, Chammeth, and Kemo Strour, Roland called the other members of the Witch Alliance, Carter, Ironaxe, and Barov, and in order to accommodate the twenty-odd people, the test site was chosen in the fifth laboratory, which has the largest space. Pen @ fun @ pavilion wWw. ｂｉｑUｇE。 ｉｎｆｏ

For the first attempt, the fractionation vessel was not too large, about a person tall and a meter in diameter, resembling a tower. The inside of the vessel is divided into three layers, with the lowest layer for air intake and the top two layers for exhaust.

Before the separation began, Roland gave everyone a simple chemistry lesson, telling them what might happen, and asking a few small questions for everyone to find their own answers to—not only to arouse the interest of the listeners, but also to greatly enhance the effectiveness of the teaching, which is also a common technique used by chemistry teachers.

“...... Theoretically, when Agatha lowers the temperature inside the container, the air will gradually condense into a liquid that will drip down to the bottom layer through the perforated partition. So when you observe an effusion at the bottom, let us know. ”

Since it is impossible to see directly, it is up to Sylvie to observe through the container and describe the changes, so Roland goes into particular detail in this part.

Sylvie nodded incredulously, "Can you really see the liquid appear? It can't be the vapor in the jar, right?"

"Rest assured, Air Liquide is pale blue, completely different from water vapor. Roland waved his hand, "And at that temperature, the water vapor would have solidified into ice crystals." Then he gestured to Elgertha, "Then begin." ”

"Wait...... Doesn't this hole in the bottom of the container need to be plugged?" she asked.

"I'll block it later, otherwise there will be too little air in the jar to see obvious changes. Since it was only an experiment, Roland chose the easiest way to inhale – when the temperature inside the tank drops rapidly, the pressure decreases, causing the outside air to pour into the tank. This is not worth the cost of normal production, because the cold air will be constantly lost and energy will be wasted, but Agatha uses magic power, and the cooling efficiency is far more efficient than any refrigerator, so Roland is too lazy to prepare the air pump to inflat.

Agatha took a deep breath and pressed her hands to the fractionation column.

After a few breaths, there was a whistling sound in the air intake pipe, which was the sound of a rapid influx of air. Layers of hoarfrost emerge around the nozzle at a visible rate and continue to expand - the moisture in the air quickly condenses at the overflowing low temperature and clings to the outer wall of the container. Anna turned the black fire into silk threads, cleaning away the thickening ice crystals.

After a while, Sylvie said in surprise, "I see liquid on the partition, but more white cream. ”

"The white frost could be an influx of water vapour or crystallized carbon dioxide," Roland explains, "and most of it should be water vapour given the very low levels of carbon dioxide in the air." ”

If the air is pumped into the fractionation column before it is officially produced, it must be dried first, otherwise the water vapor will easily block the layered plate and exhaust hole after condensation, which will reduce the production efficiency.

After about a quarter of an hour, Sylvie reported that the bottom of the container had been filled with blue liquid, and Roland had Soroya block the intake pipe and seal it with a coating.

Next is the critical warming-up.

According to the different melting and boiling points of nitrogen and oxygen, nitrogen will first reach the boiling point and escape upwards as a gas, thus achieving separation. He couldn't remember the exact value of this temperature, and there was no means to measure it at the moment, so he had to rely on Agatha to grasp it herself. This is manifested in the fact that gas is discharged from the vent hole at the top of the fractionation column, and the liquid remaining at the bottom will become bluer and bluer, which means that the purity of the liquid oxygen is constantly improving.

Fortunately, Agatha is no stranger to the control of magic, and she precisely adjusts the cooling amplitude so that it slowly rises, and after a while, Sylvie also observes the boiling of the liquid surface. Bubbles began to bubble up in the coated tubes that flowed into the water, and Kaimo quickly collected several bottles of gas using the drain gas collection method.

"Is this nitrous?" Lily pouted, "and you can't see anything." ”

"That's the first question I asked," Roland asked, "how do you prove that it's different from air?"

"Ignite," Tilly replied first, "Elementary Chemistry says that oxygen is needed for combustion, and if it's another gas, it should make the burning wood go out instantly. ”

"Just cool it back down into a liquid," said Agatha after a moment's thought, "didn't you say that nitrogen is colorless when liquefied?"

Or to export the liquid left in the container and prove that the latter is pure oxygen can also prove the diversity of the air composition. Anna began.

The scene has completely become a stage for the performance of the top students, and the test methods are proposed one by one, and then discussed with each other, and only the voices of a few people are left in the laboratory. Roland looked around and found Nightingale, Andrea, Maisie and other witches, as well as the town hall steward and chief knight Carter, all at a loss. Iron Axe, the commander of the First Army, maintained an expression at all times, and probably nodded yes no matter what he said.

Well, Roland sighed inwardly, it seems that this chemistry class is a little overrun.

If there is anyone who can feel the joy of His Royal Highness the Prince, I am afraid that the only ones left are Camo Stoil and Chames.

"Your Highness, this is really ...... Miraculous," exclaimed the young alchemist, "you have proved the correctness of Elementary Chemistry. I'm afraid that all alchemists would not have expected that even the air that can be seen everywhere around them is so complicated. ”

"With pure oxygen, wouldn't it be possible to observe more intense oxidation reactions?" I have a lot of experiments that I want to do," Kemo said excitedly.

Roland nodded, but another thought suddenly popped into his mind.

Nitrogen is the main raw material for the artificial synthesis of ammonia, which can be obtained by reacting with hydrogen under the conditions of high temperature and high pressure plus catalyst, which can not only be used to make nitrogen fertilizer, but also used to synthesize nitrogen oxides, so as to produce nitric acid. However, there is still a lot of work that needs to be done to make this process a reality, such as air pumps, vacuum gas tanks, and a series of complex reaction equipment. Even if the blank paper can provide the function of a catalyst, it will take trial and error.

Now that he has pure oxygen and pure nitrogen, why not just produce nitric oxide?

It is true that the chemical industry chooses to use ammonia to produce nitric acid because the reaction of oxygen and nitrogen is an energy-absorbing reaction, which cannot be carried out spontaneously, and requires external energy supply, such as discharge, which is achieved by instantaneously heating the gas to thousands of degrees through an electric arc, which is also the reason why the soil is more fertile in places where thunder is frequent. Because of this, this method is highly demanding and consumes a lot of energy, so it is not suitable for formal production.

However, if there is an urgent need to increase production capacity, this production method is the most efficient, and even a catalyst is not needed, only continuous discharge...... Or use other means to achieve the high temperature generated by the arc.

Roland naturally thought of Black Fire.

The heating efficiency of black fire is no worse than that of electric arc, and the burden on Anna is also extremely low, as long as the nitrogen and oxygen are purified and mixed in proportion and poured into a closed reactor, nitric oxide can be continuously generated.

He decided to give it a try.

. (To be continued.) )