Which of the following best describes the reaction seen below? 2H2(g) + O2(g) =

When the two variables is directly proportional to each other, they increase or decrease depends on how much it would be. In your equation x+y where two variables is directly proportional to each other, The increase of X is drastically 2 times greater from its last value. so it means that the value of Y should be 2 times greater than its value. So the value of Y should be 2^3 or 8.