`T_(50)` of first order reaction is 10 min. starting with 10 `"mol"^(-1)` rate after 20 min is :

Options

A. `0.0693xx"mol" L^(-1)min^(-1)`
B. `0.0693xx2.5"mol" L^(-1)min^(-1)`
C. `0.0693xx5"mol" L^(-1)min^(-1)`
D. `0.0693xx10"mol" L^(-1)min^(-1)`

Answer

B

Explanation

Remainin concetration of reactant after 20 min
`=(1)/(4)xx102.5"mol"L^(-1)`
`"Rate"=kxx["Reactant"]=(0.693)/(t_(1//2))xx["Reactant"]`
`=(0.693)/(10xx2.5=0.0693xx2.5 "mol"L^(-1) min^(-1)`