Answer:
The dissolved gases play a significant role in pushing the magma upwards, towards the surface. When these dissolved gases are in large quantities within the magma, then the intruding magma is able to generate more force, pushing the magma towards the surface. As a result of which, violent volcanic eruptions take place that releases various harmful gases. If the silica content is high and the magma comes in contact with water then it leads to a heavy explosion.
These dissolved gases are mostly Carbon dioxide (CO₂), sulfur dioxide (SO₂), hydrogen sulfide (H₂S) and a certain amount of water vapor (H₂O).