Question

23. A first order reaction has a specific reaction rate of10⁻² s⁻¹. How much time will it take for 20 g of thereactant to reduce to 5 g?
(1) 238.6 second
(2) 138.6 second
(3) 346.5 second
(4) 693.0 second

Answer 1

Answer:

Explanation:

We know that for a first order reaction

t=2.303klog.aa−x

Here, initial concentration a=10g and concentration left after time ts=2.5g

i.e., (a−x)=2.5g,

Specific reaction conctant k=10−3s−1

∴ Time required for the reactant to reduce to 2.5g

=2.30310−3×log4=2.30310−3×0.6021 (Given log4=0.6021)

=1386.6s