Acid Splash 3e FAQ
Does spell resistance apply to Acid Splash in D&D 3e?
Yes. Acid Splash is subject to spell resistance in D&D 3e. Hitting the target with the spell's ranged touch attack is therefore not always enough: if the target has spell resistance, the caster must also successfully overcome that resistance for Acid Splash to affect it. This differs from the later D&D 3.5e version, where Acid Splash has Spell Resistance: No.
Spell resistance is one of the most important edition-specific differences in Acid Splash. The original D&D 3e version allows spell resistance, while the revised 3.5e version does not. Players moving between those editions can therefore reach different answers even though both spells have the same name and many of the same basic mechanics.
The 3e version allows spell resistance
In D&D 3e, Acid 
D&D Portal - Acid Damage type Acid is a damage type used by attacks,
spells, class features, resistance, immunity, and vulnerability. Full link: https://dnd-portal.com/rules/damage-types/acid/ Splash is listed as a spell to which spell resistance applies.
That means a creature with spell resistance has an additional defense against the spell beyond the ranged touch attack.
A creature without spell resistance does not gain this additional defensive step.
The touch attack and spell resistance are separate checks
The ranged touch attack determines whether the Acid D&D Portal - Acid Damage type Acid is a damage type used by attacks,
spells, class features, resistance, immunity, and vulnerability. Full link: https://dnd-portal.com/rules/damage-types/acid/ projectile successfully connects with the target.
Spell resistance determines whether the magic can actually affect a resistant creature.
A successful ranged touch attack therefore does not automatically mean the spell deals damage to a creature with spell resistance.
The caster must overcome spell resistance
When Acid D&D Portal - Acid Damage type Acid is a damage type used by attacks,
spells, class features, resistance, immunity, and vulnerability. Full link: https://dnd-portal.com/rules/damage-types/acid/ Splash is used against a creature with spell resistance, the normal spell-resistance rules determine whether the spell penetrates that defense.
If the caster fails to overcome the creature’s spell resistance, Acid D&D Portal - Acid Damage type Acid is a damage type used by attacks,
spells, class features, resistance, immunity, and vulnerability. Full link: https://dnd-portal.com/rules/damage-types/acid/ Splash does not affect that creature even if the ranged touch attack itself was successful.
If the caster successfully overcomes spell resistance, the spell can resolve normally and deal its Acid D&D Portal - Acid Damage type Acid is a damage type used by attacks,
spells, class features, resistance, immunity, and vulnerability. Full link: https://dnd-portal.com/rules/damage-types/acid/.
Spell resistance and acid resistance are different
Spell resistance protects against the magical effect of Acid D&D Portal - Acid Damage type Acid is a damage type used by attacks,
spells, class features, resistance, immunity, and vulnerability. Full link: https://dnd-portal.com/rules/damage-types/acid/ Splash. Resistance to Acid D&D Portal - Acid Damage type Acid is a damage type used by attacks,
spells, class features, resistance, immunity, and vulnerability. Full link: https://dnd-portal.com/rules/damage-types/acid/ deals with the damage type after the spell is able to affect the creature.
A creature can therefore have spell resistance, Acid D&D Portal - Acid Damage type Acid is a damage type used by attacks,
spells, class features, resistance, immunity, and vulnerability. Full link: https://dnd-portal.com/rules/damage-types/acid/ resistance, both defenses, or neither.
Overcoming spell resistance does not cause the spell to ignore resistance or immunity to Acid D&D Portal - Acid Damage type Acid is a damage type used by attacks,
spells, class features, resistance, immunity, and vulnerability. Full link: https://dnd-portal.com/rules/damage-types/acid/.
Why 3e and 3.5e give different answers
Acid D&D Portal - Acid Damage type Acid is a damage type used by attacks,
spells, class features, resistance, immunity, and vulnerability. Full link: https://dnd-portal.com/rules/damage-types/acid/ Splash was revised when it became part of D&D 3.5e. One of the mechanical changes was its interaction with spell resistance.
The 3e version allows spell resistance, while the 3.5e version explicitly does not.
This is why a ruling, character guide, or rules discussion written for one edition should not automatically be applied to the other.