N2+3H2 → 2NH3 . Correct representation of rate of reaction is
Rate = ΔN2Δt = 13ΔH2Δt = −12ΔNH3Δt
Rate = −ΔN2Δt = −3ΔH2Δt = −2ΔNH3Δt
Rate = −ΔN2Δt = −13ΔH2Δt = +12ΔNH3Δt
Rate = −ΔN2Δt = −13ΔH2Δt = −12ΔNH3Δt
Concentration of reactant decreases with time.
∴ denoted by negative sign.
Coefficients of reactants and products must be written as reciprocals