In a reaction 2HI ⟶ H2 + I2, the concentration of HI decreases from 0.5 mol L–1 to 0.4 mol L–1 in 10 minutes. What is the overall rate of reaction during this interval?

Average Rate of 2 2 2HI H I -> , Now, rate of reaction can be expressed as 2 2 1 2 HI H I t t t 3 1 0.4 0.5 1 Rate of reaction 5 10 min 2 10mins x x ∴Rate of reaction 3 5 10 x M min-1