Chapter 204: Methods for generating hydrogen sulfide

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

Naturally, it was the bath powder that she got from her agent, Miss Itakura Misaki, two days ago. She bought it at Kosenan and asked her to give it to Okino Yoko.

Two days ago.

A woman named Mayumi Motoki and actor Jōichi Matsutani used bath additives and laundry detergent to create hydrogen sulfide, killing actor Kenji Furusawa.

And in the early hours of this morning, Akikawa also created hydrogen sulfide gas, weakening the mobility of Vermouth and Chianti in Kunio Koizumi's room.

Akikawa Kyousuke was not worried that he would be suspected of following the same methods as Mayumi Motoki and Jōichi Matsutani.

Because with the methods they used, the hydrogen sulfide produced was not enough to poison Chianti and others.

In the past, there were many cases in Japan where people committed suicide by using bath additives and laundry detergents to generate hydrogen sulfide gas, which resulted in the death of the entire family.

But whether it was the previous murder of Kenji Furusawa or the frequent suicides in Japan with bath additives, they all happened "indoors."

The reaction between bath additives and laundry detergents is mainly due to the "sulfide" in the bath additives reacting with the "acid" in the laundry detergent to produce hydrogen sulfide.

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

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

But the situation last night was different. Akikawa did not have the conditions to generate hydrogen sulfide gas directly in Koizumi 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 is not enough to produce enough hydrogen sulfide to poison everyone in the room.

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

Therefore, the substance that Akikawa chose to react with the bath additive was not laundry detergent, but "detergent".

"Muric acid" is often found in cleaners used to treat stubborn stains, remove scale or clean areas such as bathrooms and toilets.

Hydrochloric acid is classified as a "strong acid" and is very corrosive and reactive, effectively dissolving mineral deposits, rust, and other difficult-to-remove stains.

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

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

Akikawa Kyousuke conservatively estimated that a 100-gram bath additive contains 10%, or 10 grams, of magnesium sulfide.

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

Akikawa has seen Kunio Koizumi's room and estimated that the volume of Kunio Koizumi's room is about 70 cubic meters.

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

The so-called "sufficient amount of hydrochloric acid" is actually not that much.

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

The concentration of hydrochloric acid in regular cleaning agents is 15%.

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

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

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

Akikawa Kyousuke took into account the possible loss of water that might evaporate in the yard, so to be on the safe side, he used a total of six bath additives.

After having the reactants that react to produce hydrogen sulfide, another indispensable item is the container for bath agents and cleaning agents.

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

So all they could do was put the bath additives and cleansers into containers and then throw them into Kunio Koizumi's yard while they were reacting.

But this brings up a problem: the hardness of the container cannot be too strong.

The container used for Kosenan's detergent is made of the most common detergent bottle material on the market.

High density polyethylene.

If Akigawa had stuffed the bath additive into the bottle of detergent, screwed on the lid and threw it into Koizumi Kunio's yard,

the bath additive and detergent would react to produce enough hydrogen sulfide gas and the bottle would certainly not be able to withstand the increased internal pressure and would explode.

Once the explosion occurs, not only will Vermouth and Chianti in the room become alert,

The bath additives that were blown away can no longer react with the cleaning agent to produce hydrogen sulfide gas.

So in order to avoid this situation, Akikawa poured the detergent into a mineral water bottle, stuffed the bath spray in it, and threw it into Kunio Koizumi's yard.

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

In this way, the bath agent and the detergent can continue to react, while the bottle can be prevented from exploding and making a loud noise, alerting the enemy.

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

If Akikawa Kyousuke entered the room with a high concentration of hydrogen sulfide, he would also be poisoned.

Akikawa Kyousuke didn't have a gas mask, and ordinary masks could not filter out hydrogen sulfide molecules.

It is not difficult to solve this problem either.

Both water and activated carbon can absorb hydrogen sulfide gas.

So Akikawa Kyousuke wet the towel and covered his face with it, and at the same time added a layer of activated carbon between the wet towel and the mask.

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

Akikawa Kyousuke took out the activated carbon from 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 not comparable to that of a real gas mask, it is enough for Akikawa to buy himself enough time before hydrogen sulfide affects his actions and thinking.

After Akigawa drove away Vermouth, he came to Kunio Koizumi's yard and picked up the bottle he used to generate hydrogen sulfide.

Then you just need to simply 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.

But when Akikawa Kyousuke 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.

(End of this chapter)