Go to nationalgeographic.com (maybe its natgeo.com for short) or on Netflix to watch a documentary(one of my favorite sources to get enlightened). Is it just me or everytime I watch a volcano erupt I think of that red hard candy they pour over candied apples? And I've heard and understand what the smoke and fumes from a volcano smell like but fingernail polish remover always comes to mind.
When the volcano erupts, it causes a mounting pressure of gas that has developed in the magma. The pressure causes the magma to be strained onto the Earth's surface as lava. It solidifies on the surface to form volcanic ash.