In Conan, people have a brain option system

One of the reactants used by Akikawa Kousuke to react to generate hydrogen sulfide gas,

Naturally, it was the bathing agent that she got from the agent Miss Itakura Misaki two days ago. She bought it at Kosenan and gave it to Okino Yoko.

Two days ago.

A woman named Mayumi Motoki and actor Shoichi Matsutani used bath chemicals and laundry detergent to create hydrogen sulfide, killing actor Takeshi Furusawa.

In the early hours of this morning, Akikawa Kosuke also produced hydrogen sulfide gas, which weakened the mobility of Belmode and Chianti in the male room of Koizumi Kununi.

Akikawa Kyusuke is not worried that he will be suspected of copying the methods of Mayumi Motoki and Shoichi Matsutani.

Because with their methods, the hydrogen sulfide generated was not enough to poison Chianti and others.

In the past, many people in Japan committed suicide by using bath chemicals and laundry detergent to generate hydrogen sulfide gas, resulting in the death of their entire family.

But whether it was the previous murder of Takeshi Furusawa or the frequent suicides by bathing agents in Japan, this all happened "indoors."

The reaction between bathing agent and laundry detergent mainly relies on the "sulfide" in the bathing agent and the "acid" in the laundry detergent to react to generate hydrogen sulfide.

The acid contained in laundry detergent is usually "citric acid" or "lactic acid", which are both "weak acids".

If it is in a poorly ventilated room, the generated hydrogen sulfide gas will not easily diffuse out, so even if the bath agent only reacts with weak acid, it is enough to poison a whole family.

But the situation was different last night. Akikawa Kousuke did not have the conditions to directly generate hydrogen sulfide gas in Furuzumi Kunio's room.

Therefore, it can only be generated in Kunio Koizumi's yard.

In this case, the weak acid in the laundry detergent alone cannot generate a dose of hydrogen sulfide that is enough to poison everyone in the room.

Because the reaction rate is too slow, hydrogen sulfide gas will quickly dissipate as soon as it is generated.

Therefore, the substance Akikawa Airsuke chooses to react with the bathing agent is not laundry detergent, but a "cleaning agent".

Cleaners used to treat stubborn stains, descale or clean areas such as bathrooms and toilets often contain "hydrochloric acid".

Hydrochloric acid is a "strong acid" that is highly corrosive and reactive and can effectively dissolve mineral deposits, rust and other difficult-to-remove dirt.

At the same time, it reacts with the magnesium sulfide in the bathing agent, almost completely ionizing it, and can quickly provide a large amount of hydrogen ions.

Therefore, the rate of hydrogen sulfide generation will be dozens of times or even more than that of citric acid or lactic acid contained in laundry detergent.

Akikawa Kyusuke conservatively estimates that a 100-gram bath agent contains 10%, or 10 grams, of magnesium sulfide.

Then it reacts with a sufficient amount of hydrochloric acid to produce up to 3.97 liters of hydrogen sulfide gas.

Akikawa Kusuke had seen Kunizumi Kunio's room, and he estimated that the volume of Kunizumi Kunio's room would be about 70 cubic meters.

Then the concentration of 3.97 liters of hydrogen sulfide gas entering the room is approximately 57ppm.

The so-called "sufficient amount of hydrochloric acid" actually does not require much.

Only about 13 grams of hydrochloric acid is needed to completely react 10 grams of hydrogen sulfide.

The usual concentration of hydrochloric acid in detergents is 15%.

In other words, a 500 ml bottle of detergent is enough to completely react the magnesium sulfide in five pieces of bath detergent.

The concentration of the generated hydrogen sulfide gas after entering the room reached 280ppm.

This is "high-concentration hydrogen sulfide exposure" that is life-threatening.

Akikawa Kyusuke considered the loss that might evaporate in the yard, so to be on the safe side, he used a total of six pieces of bathing agent.

After having the reactants that react to generate hydrogen sulfide, another indispensable thing is the container for bath agent and cleaning agent.

It is impossible for Akikawa Kyousuke to generate hydrogen sulfide gas in his room or in the corridor.

So the only option was to put bath soap and detergent into containers, and then throw them into Koizumi Kunio's yard while they were reacting.

But this time involves a problem, the hardness of the container cannot be too strong.

The container used by Kosenan’s detergent is the most common detergent bottle material on the market——

High density polyethylene.

If Akikawa Kyousuke just stuffed the bath agent into the detergent bottle, screwed on the cap and threw it into Furuzumi Kunio's yard,

When the bath solution reacts with the cleaning agent to produce enough hydrogen sulfide gas, the bottle will definitely be unable to withstand the increased internal pressure and explode.

Once it explodes, Belmode and Chianti in the room will be wary.

The blown bath agent can no longer react with the cleaning agent to generate hydrogen sulfide gas.

So in order to prevent this from happening, Akikawa Kosuke poured the detergent into the mineral water bottle, stuffed the bath agent into it, and threw it into Koizumi Kunio's yard.

Mineral water bottles are made of low-density polyethylene, a flexible material that is more likely to deform and produce small cracks when under pressure, rather than suddenly exploding.

In this way, it can not only ensure that the bath agent and the cleaning agent continue to react, but also prevent the bottle from exploding and making a loud noise to alert others.

In addition, there is another issue that must be considered.

Even if Akikawa Kousuke entered a room containing a high concentration of hydrogen sulfide, he would also be poisoned.

Akikawa Kousuke did not have a gas mask, and ordinary masks could not filter out hydrogen sulfide molecules.

It is not difficult to solve this problem.

Both water and activated carbon can absorb hydrogen sulfide gas.

So Akikawa Sosuke wet the towel and covered his face, and added a layer of activated carbon between the wet towel and the mask.

Activated carbon is usually used for refrigerator deodorization or air filtration.

Akikawa Sosuke took out the activated carbon in the air purifier in the room and placed it between the wet towel and the mask.

In this way, a simple gas mask is ready.

Although the filtering effect is difficult to compare with the real gas mask, it is enough for Akikawa Sosuke to buy enough time for himself before hydrogen sulfide affects his actions and thinking.

When Akikawa Sosuke drove away Vermode Chianti, he came to the yard of Koizumi Kunio and picked up the bottle he used to generate hydrogen sulfide.

Then you only need to rinse the bottle with hot spring water to clean the reactants inside.

Natural hot springs contain a small amount of sulfide.

Therefore, it is impossible to detect the composition of the reactants in such a large hot spring pool.

And when Akikawa Sosuke turned up the temperature and wind speed of the air conditioner and discharged the hydrogen sulfide gas in the room to the outside, there was no evidence at all.