Concentration of the limiting reactant (with initial concentration of a moles/litre) after time t is (a-x). Then ‘t’ for a first order reaction is given by____________________?
A. k. t = ln a/(a – x)
B. k. t = x/a (a – x)
C. k. t = ln (a – x)/a
D. k. t = ln a (a – x)/x