Question

What is the meaning of positive sign in average rate of the reaction?

Answer 1

Positive rates are conventionally used to signify the formation of species in the average rate of the reaction.

Example:

If the rate of reaction is given as:

$-\frac{d\left[A\right]}{dt}=+\frac{d\left[b\right]}{dt}$ here the positive sign shows that the formation of product B.