Question

for the reaction of hydrogen with iodine

H2(g) + I2(g) --> 2HI(g)

relate the rate of disappearance of hydrogen gas to the rate of formation of hydrogen iodide.

and my answer is:

rate formation of HI= delta [HI]/delta t
and the rate of reaction of I2 = delta [I2]/ delta t

to make 1/2 delta [HI]/ delta t = delta -[I2]/ delta t

Answer 1

That looks ok except the question is for H2 and not I2.

Answer 2

so change every I2 to H2