5 analyzing explain why silica - rich magma and magma that contains gas erupt explosively.

Brief Explanations:

Silica - rich magma has high viscosity due to the long - chained silica polymers. High viscosity traps gas bubbles. As the gas pressure builds up from the trapped gas in the viscous magma, it eventually leads to an explosive eruption when the pressure exceeds the strength of the confining rock.

Answer:

Silica - rich magma is viscous and traps gas. As gas pressure builds up, it causes explosive eruptions.