JEE Advanced levelSingle correct optionDifficulty 3 of 3ck188
For 2AP, the measured concentrations of A are 1.000M at 0 s, 0.670M at 20 s and 0.301M at 60 s. The best estimate of the rate of reaction (IUPAC, per unit stoichiometric coefficient) at 40 s using only the readings at 20 s and 60 s, in Ms−1, is
A4.61×10−3
B9.22×10−3
C1.84×10−2
D5.83×10−3
Answer: A
The instantaneous rate at 40 s is approximated by the slope of the chord symmetric about it: −Δ[A]/Δt=(0.670−0.301)/40=0.00923Ms−1. This is the rate of loss of A; the rate of reaction divides by νA=2, giving 4.61×10−3Ms−1.