Alkali (3.5e Equipment)
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Corrosive alkalis deals 1d6 points of damage per round of exposure except in the case of total immersion (such as into a vat of alkali), which deals 10d6 points of damage per round. An attack with alkali, such as from a hurled vial or a monster's spittle, counts as a round of exposure. The fumes from most alkalis are inhaled poisons. Those who come close enough to a large body of alkali to dunk a creature in it must make a DC 13 Fortitude save or take 1 point of Constitution damage. All such characters must make a second save 1 minute later or take another 1d4 points of Constitution damage.
Creatures immune to alkali's caustic properties might still drown in it if they are totally immersed (see Drowning).
Flask of alkali
You can throw a flask of alkali as a splash weapon. Treat this attack as a ranged touch attack with a range increment of 10 feet. A direct hit deals 1d6 points of alkali damage. Every creature within 5 feet of the point where the alkali hits takes 1 point of alkali damage from the splash.
Acid and alkali
When acid and alkali are mixed, the result is a violent reaction. The explosion deals 3d6 Fire damage to creatures on its square and 1d6 Fire damage to creatures on adjacent squares. This neutralizes one flask worth of acid and one of alkali. For large amounts of acid or alkali, the reaction may occur more than once per round as long as there is sufficient acid and alkali. This damage also occurs when a creature affected by acid arrow or a similar effect is splashed with alkali. Against an acidic Ooze, the reaction does an additional 1d6 damage + 1d4 Con damage to the ooze.
Like acid, alkali can be made with a DC15 Craft(Alchemy) check.