12 October 2021

Volcanic hydrochloric acid production


The toxic soup of volcanic gases (carbon monoxide, carbon dioxide, sulfur dioxide, hydrogen sulfide) is familiar to most everyone.  Today I learned about a new one being produced on La Palma in the Canaries:
One river of lava reached the ocean near Playa de Los Guirres on Sept. 28. It poured off a 300-foot-tall cliff into the seawater below, prompting authorities to urge residents to remain indoors with their windows closed to limit the entry of outside air. When lava enters the ocean, it heats up seawater extremely rapidly, splitting water molecules into hydrogen and oxygen ions. Some of the hydrogen combines with chlorine ions in the seawater to form hydrochloric acid and produce a gas that is toxic when inhaled.
You learn something every day (though hydrochloric acid shouldn't exist as a gas - perhaps they mean hydrogen chloride, or else the HCl is aerosolized as inhalable droplets).  

Image cropped for size from the original. 

1 comment:

  1. HCl, hydrogen chloride is a gaseous molecule at ambient circumstances. As a strong acid, it will dissolve and split as soon as it encounters water turning into hydrochloric acid. Now sources of water as water vapor in the air, and 70% of your body.

    The bottles of HCl you buy are solutions of the gas in water. They fume. Much like ammonia.

    Another fun fact: Kilauea on Hawaii emits hundreds to thousands of tons (as in the weight unit) of SO2 a day (when it's not filled with lava like the last few weeks). SO2 dissolves in water to become H2S03, which will degrade into H2SO4, sulfuric acid. Remember that most of Hawaii has nice warm humid air.

    I've worked with both. From personal experience I can assure you they're not fun to inhale, even very small whiffs. On the other hand, they're excellent in teaching you to work properly in your fumehood.

    Because lava is so hot, it emits all kinds of stuff. Fun odd chemistry. Mostly not fun to inhale.

    https://www.usgs.gov/faqs/how-much-sulfur-dioxide-so2-gas-does-k-lauea-emit?qt-news_science_products=0#qt-news_science_products

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