Considering the concept of surface area affecting the rate of reaction, explain why grain storage silos sometimes explode spectacularly?

The smaller a particles the higher the surface area to volume ratio

Explanation:

In a grain silo, there are lots of minute dust grain particles and chaff floating in the air. The silo is important in keeping the grains dry hence there is little moisture. These particles, when concentrated, are therefore highly combustible and the slightest spartk can cause a spectacular explosion.  

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