For the first order reaction:

1.	For the first order reaction:
Answer» The concentration of reactants decreases exponentially with time The half life of the reaction decreases with INCREASING temperature. The half-life of the reaction depends upon initial concentration of the REACTANT The reaction proceeds to `99%` completion in eight half life periods. Solution :(a,b,d) a) For first order reaction, concentration of reactants decreases exponentially with time (True statement). `[A]=[A]_(0)e^(-kt)` ALSO `t_(1/2)= (0.693)/k` b) the `t_(1//2)` period decreases with increasing temperature because reaction rate generally increases with increase in temperature. (True statement) d) The reaction proceeds to `99.6%` completion in eight half life duration. (True statement). `k=(2.303)/(t_(99.6%)) log 100/0.4 = (2.303 log 250)/(t_(99.6%))` ..........(i) `k=0.693/t_(1//2)`...........(ii) Divide eqn. (i) to with (ii) `(2.303 xx 2.4)/(t_(99.6))= 0.693/t_(1//2)` `t_(99.6) = (2.303 xx 2.4)/(0.693) xx t_(1//2)` `=7.975 xx t_(1//2) ~~ 8 xx t_(1//2)`. Statement (C) is incorrect.

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