Question

water should not be used to put of electrical fires (or) buring oil and petrol .instead sand (or) soil should be used why?

Answer 1

because water is good condutor of electricity so electricity will easily pass through it

Answer 2

water should not be used to put out electrical fires because it is a good conductor if electricity and I should also not be used to put out burning oil or petrol because they are lighter than water and thus the will float on it and continue burning. in both the cases using sand is a good option because it cuts out air passage and thus doesn't allow the fire to get the oxygen it needs to continue burning and so the fire gets put out.
hope it helps you