For a reaction A`to` B, the rate of reaction can be denoted by `-(dA)/(d t) or ( dB)/( dt)`State the significance of plus and minus signs in this case.

Explanation

Rate of reaction is always positive. If rate is measured in terms of conc. of reactants, dA is negative and a negative sign is put to make the rate positive.
` dA =- ve , ` rate ` = - (d [A])/( dt ) = (-) xx (-) = + ve `
If rate of reaction is measured in terms of concentration of products, d[B] is positive and rate is also positive. Hence, negative sign is not put before d[B]