A vial can contain up to 4 ounces of liquid (PHB, page 153).
Assuming that a bottle of basic poison contains a total of 4 ounces of poison, then this gives us 25% weapon coverage per ounce of poison (or 12.5% per half ounce) and 75% coverage in 1 piece. of ammunition per ounce (or 37.5). % coverage in 1 piece of ammunition for half an ounce).
In short, you could not cover a single piece of ammunition, let alone a weapon, with the half ounce of poison produced by the alchemical jar.
At your discretion, a partial dose of poison can have (reduced) effects.
The DMG (257-258) distinguishes between different types of poisons and how they work, by contact, inhalation, injury or Ingested (DMG 257):
Ingested A creature must swallow a full dose of poison ingested to suffer its effects. You can decide that a partial dose has a reduced effect, such as allowing an advantage on the saving throw or inflicting only half the damage on a failed save.
Handle it at your discretion. You may want to use the Variant rule on the same page (DMG 136) that makes identification in general more difficult and adjust it by making it explicit that testing potions is dangerous or has no effect.
The narration of the poisons is also mostly at your discretion, you define if they are tasteless, without smells, indistinguishable (for that matter, they also narrate the smell and taste of the magic potions and can enjoy those healing potions without flavor or the like) . soap), etc. How the identification potions should work gives narrative techniques.
In What happened to the disease in D & D 5e? We see that the disease may not be a specific mechanic. However, it seems to be quite combined with the poison, for example:
Here is an example of a real disease of another disease plagued by the classic Otyugh (from the HOTDQ supplement)
If the target is a creature, it must succeed in a saving throw of the DC 15 Constitution against the disease or be poisoned until the disease is cured.
In this case, it is the saving throw "against the disease" or "against the poison" (for the purposes of the poison mechanic versus the resistance of the dwarf poison). I think that by reading this post, some may say that the "against the poison" of the resistance of the dwarves is specifically against the poisoned condition.
Similarly, bottle fever in the SRD says:
A child who drinks stale alcohol must succeed in a saving throw of the DC 12 Constitution or in a bottle fever contract. The first symptoms of bottle fever begin to appear in 1d10 hours. An infected creature emits a strong odor of alcohol. When the creature performs an act that requires physical effort, such as climbing a wall or fighting, it must succeed in a saving throw of the DC 10 Constitution or be poisoned for 1 hour. If the creature succeeds in the saving throw, it does not need to make another save roll for this effect for 1 hour.
If the disease gives the condition "poisoned", as in the case of Otyyugh, does the resistance of the dwarves apply?
If the disease gives the condition "poisoned" later, as in bottle fever, in which one would have to fail twice, does the resistance of the dwarves apply to the first, the second, to the other or the other does not?
But assuming we're talking Injury poisons, they say:
Injury: these poisons are released mainly through the attacks of certain creatures and through weapons covered with the toxin. Poisons from injuries usually do not have a start time and have a frequency of 1 round.
Once, when you take the initial damage, and once again each round.
Poisons for injuries (mostly) apply their damage in each round for its duration, as described in Afflictions:
Frequency: this is the frequency with which the release of periodic safeguard should be attempted after the affliction has been contracted (after the start time, if the affliction has any). While some afflictions last until they are cured, others end prematurely, even if the character is not healed by other means. If an affliction ends after a certain time, it will be written down on the frequency. For example, a disease with a frequency of "1 / day" lasts until it is cured, but a poison with a frequency of "1 / round for 6 rounds" ends after 6 rounds have passed.
Afflictions without a frequency occur only once, immediately after the contraction (or after the start time, if there is one in the list). Keep in mind that there are poisons with a different frequency, such as 1 / minute or even 1 / day.
Now, consider the area in bold, "If the affliction has any", why…
Poisons without initiation will not cause initial damage.
Again, as described in Afflictions:
Start: some afflictions have a variable amount of time before settling. Creatures that come into contact with an affliction with a The start time must make a saving throw immediately.. Success means that affliction is avoided and no more saving throws should be made. Failure means that the creature has contracted the affliction and must begin to make additional saves once the start period has elapsed. The effect of the affliction does not occur until after the start period has elapsed and only if more saving throws fail.
Remember when I dared "If the affliction has any"? Well, here is our case. If the poison does not have Start, then it simply never causes initial damage, only frequency damage. Such is the case of Adder Black Venom.
Therefore, to specifically answer your question, it will only cause damage (up to) 6 times, once per round in your frequency if the target fails your saving throw.
According to the description of the Devotion Stock Exchange:
This bag seems to be an ordinary sack. The detection of magical properties makes it look like it's a possession bag. The sac, however, is something completely different and more insidious: one of the feeding holes of an extradimensional creature.
Specifically, the part of the "feeding hole" implies that something eats what you put into it.
Could you put poison or something similarly harmful / lethal inside the bag to kill the extradimensional creature?
After the PHB 2018 errata, the spell Contagion now inflicts venom as a condition for a successful melee spell attack. The text of the relevant spell is below, with the updated parts highlighted in bold:
Your touch inflicts diseases. Make a melee spell attack against a creature within reach. In one hit, the target is poisoned.
At the end of each turn of the poisoned target, the target must make a Constitution save roll. If the target achieves three of these saves, he is no longer poisoned and the spell ends. If the target fails three of these saves, the target is no longer poisoned, but chooses one of the following diseases. The target is subject to the chosen disease for the duration of the spell.
Since this spell induces a natural disease in its target, any effect that eliminates a disease or that otherwise improves the effects of a disease applies to it.
The wording of the spell leads me to conclude that this spell still inflicts a disease, which has the immediate effect of poisoning the target. Therefore, even if an objective has immunity to the poison, they will continue to make the liftings of the Constitution as designated to see if the disease has an effect.
However, the line, "At the end of each turn of the poisoned target …" It also leads me to think that an enemy with poisonous immunity can not be the target poisoned, therefore, does not allow the remaining sequence of events.
They are targets with immunity to Poisoned condition therefore immune to Contagion?
The closest you can get to this is perhaps a double-edged sword and a multiple attack.
Suppose your goal is to get 2d4 instead of just 1d4 of that poison damage in a single turn, with only one weapon, and without reapplying the poison once the combat has begun.
As Purple Monkey correctly pointed out, this will not work when coating, for example, the same sword more than once with basic poison and then attack with him, if such poison counts as a "game effect" mentioned in the DMG errata (which probably should be).
However, does the player have a double-edged sword and a multiple attack? Then he could cover both blades just before jumping into the fray, and potentially get the 1d4 poison in both attacks (if they hit), because they no longer happen "at the same time".
If you want to dominate the house (or if you read the DMG errata as unclear about whether mundane poison is a "game effect"), as the sixteenth-century toxicologist Paracelsus said, "the dose makes the poison". However, there is a non-linear relationship between the dose of the poison and the effects (as was also observed in Paracelsus). Which means that the damage does not necessarily double when the dose is.