What happens during exposure to magma?

Lets say someone sent trash down to the magma. Would the trash forever stay in the magma? Would toxic gases be emitted? Describe on what the effects would be. Thanks.

If you're asking about molten rock, the extreme temperature would burn or melt the trash and what remains would integrate into the solid product once it cools down. Toxic gasses would depend on what's in the trash. Many plastics are toxic when they burn. The net effect would depend on what it is and how much there is.