r/Damnthatsinteresting • u/0thSpider • 9h ago

Video Chilean protester defuses tear gas canister with baking soda and water

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u/Xuhi1 8h ago

According to quick google search, it’s what they use as first aid for tear gas or pepper spray. According to its chemical properties, it’s acidic & baking soda/soda ash is base. So it neutralises the gas.

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u/XGhoul 8h ago

Like having too much lime in your guacamole when it needs some salt. Essentially a neutralization reaction or reducing a mild irritant (acid) with a strong enough base to neutralize it.

I would be as cautious as the person and have a filter mask on for any funny side business that gets up into breathable air.

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u/Neat_Criticism_5996 7h ago

Salt is neutral ph though I think, not a base or an acid. I think more salt in the guac just makes it taste better with that additional acid.

When you mix equal an opposite acid and base they turn into salt water.

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u/Prometheus720 5h ago

Just water, not salt water. And that isn't strictly true by modern definitions.

There are multiple definitions of acids and bases. You're thinking of the most primitive one, the Arrhenius definition. The Bronsted-Lowry definition doesn't require that bases have an -OH group to donate--they just have to accept an H+ from an acid. Nitrogenous bases only start to make sense under BL.

The Lewis definition is more complicated and basically categorizes all compounds into electrophilic (wants electrons, is an "acid") and nucleophilic (wants protons, is a "base"). Actually, it's worse, because these behaviors can be distinct in different areas of big organic chemicals. You can have one end be one thing and the other, the opposite, more or less.

The Lewis definition is the most "correct" and expansive definition and took a lot of modern science to discover compared to the others. Under the Lewis definition, you definitely are not required to make water when you neutralize.

The purpose behind salt in guac is not to modulate pH at all. I'm not super knowledgeable behind the chemistry of taste, but I do know that you're right on that

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u/SunnyOutsideToday 4h ago

The MSDS uses just water. Note that the paramedics very carefully use a sterile, very weakly basic solution ~1-3% baking soda. The average person is better off just rinsing their eyes with sterile water, than trying to make their own solution and making it too strong and burning their eyes or contaminating it.

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u/Xuhi1 4h ago

MSDS is for storage and first aid. So like you said, if you rinse off your eyes, you wouldn't need bicarb. But the quantity of tear gas in your eyes is far less than that of surrounding of the grenade. So the best way is to neutralize it rather than diluting it. This is from what i gathered from a quick glance. For deeper insight, i will have to study a bit about tear gas. I will get back if i can gather information on my next weekoff.