Buddy, make your acid whatever. The fine gentlemen that posted before have already told you all the things I am going to say.

However, on what grounds is it immoral?

Things only have the value that you give it, place in it. For example, giving people the middle finger is bad becase we say its bad. What is so wrong about it? Its a finger, the finger in the middle of my hand. But we choose to put a meaning on the middle finger that is associated with negativity.

Opinions on drugs are quite the same.

A lot of my stoner buds say "ahhhh I'll never do pharms because pills are manmade evils blah blah blah" They put that value into pharms, not the pharms drug itself.
My other friends say "ahhh pot wrecks your lungs blah blah blah pharms are the way to go go go!!" That is the value that they put in pharms, and the value they place in pot.

To say Acid is immoral is kind of silly.. anything can be immoral if you give it that value.