One day Mudra was talking to her mother who was cooking vegetables in a stainless steel utensils. Mudra observed that the bottom of cooking utensils was getting blackened from outside. She showed this to her mother. The mother told Mudra that the bottoms of all the cooking utensils kept on the gas stove were getting blackened for the last few days and she had tough time cleaning these utensils. Being a science student of class X, Mudra checked the gas stove thoroughly and could understand the reason for this problem. She explained everything to her mother. As Mudra was getting late for school, she asked her mother to take a particular step to stop the blackening of cooking utensils. Mudra's mother did the same. The mother was glad that the bottoms of cooking utensils kept on gas burner were no longer being blackened. Apart from blackening the utensils, state two other disadvantages in this condition.