Question

why rate of reaction is always positive or why rate of reaction can not have a negative value

Answer 1

$ASSALAMUALAIKUM$

The concentration of a reactantalways decreases with time, so and are both negative. Sincenegative rates do not make much sense, rates expressed in terms of a reactant concentration are alwayspreceded by a minus sign to make the rate come out positive.

$INSHAALLAH it will help you!$

$\mathbb{\huge{A.K.}}$

Answer 2

The concentration of a reactantalways decreases with time, so and are both negative. Sincenegative rates do not make much sense, rates expressed in terms of a reactant concentration are alwayspreceded by a minus sign to make the rate come out positive.