Can an artificer stay invisible when using Alchemical Fire/Acid?

Question

Let's say a UA Artificer (Alchemist subclass) casts invisibility on himself.

The description of invisibility says:

A creature you touch and everything it wears or carries becomes invisible. If the target drops an item or removes it, the item is no longer invisible, and if the target tries to attack or cast a spell, the spell ends early.

The artificer then uses his Alchemical Formula feature to pull Alchemical Fire or Alchemical Acid out of his Alchemist's Satchel, and subsequently throws it at an enemy.

Alchemical Fire. As an action, you can reach into your Alchemist’s Satchel, pull out a vial of volatile liquid, and hurl the vial at a creature, object, or surface within 30 feet of you (the vial and its contents disappear if you don’t hurl the vial by the end of the current turn). On impact, the vial detonates in a 5-foot radius. Any creature in that area must succeed on a Dexterity saving throw or take 1d6 fire damage. This formula’s damage increases by 1d6 when you reach certain levels in this class: 4th level (2d6), 7th level (3d6), 10th level (4d6), 13th level (5d6), 16th level (6d6), and 19th level (7d6).

Alchemical Acid. As an action, you can reach into your Alchemist’s Satchel, pull out a vial of acid, and hurl the vial at a creature or object within 30 feet of you (the vial and its contents disappear if you don’t hurl the vial by the end of the current turn). The vial shatters on impact. A creature must succeed on a Dexterity saving throw or take 1d6 acid damage. An object automatically takes that damage, and the damage is maximized. This formula’s damage increases by 1d6 when you reach certain levels in this class: 3rd level (2d6), 5th level (3d6), 7th level (4d6), 9th level (5d6), 11th level (6d6), 13th level (7d6), 15th level (8d6), 17th level (9d6), and 19th level (10d6).

Does his invisibility end? This doesn't seem to be an attack or a spell.

Answer 1

They are not attacks or spells, so you stay invisible.

We have a question that discusses what counts as an attack. In short, something is an attack if it is called an attack or you make an attack roll with it. These special options granted to the Artificer meet neither of these requirements, so the actions are not attacks. Contrast this to the standard use of alchemist's fire which says (emphasis mine):

As an action, you can throw this flask up to 20 feet, shattering it on impact. Make a ranged attack against a creature or object, treating the alchemist's fire as an improvised weapon.

Since the Artificer's version is not an attack, invisibility does not end.

Unearthed Arcana

The Artificer is currently in playtesting and will likely be subject to changes before or if it is released officially. Some of the subclasses that shoed up in Xanathar's Guide to Everything made their debut in Unearthed Arcana, but many changes were made between the versions. This is exactly the sort of thing that may be changed. For a more direct analogy, you can look at the Arcane Archer in Xanathar's Guide to Everything which treats similar effects as attacks even though they don't involve attack rolls (emphasis mine).

When you use this option, you don’t make an attack roll for the attack. Instead, the arrow shoots forward in a line, which is 1 foot wide and 30 feet long, before disappearing... Each creature in that line must make a Dexterity saving throw [or take damage].

This sort of treatment may very well be applied to the Artificer.