Question

plzz solve question no. 55

Answer 1

let Tf is half life of this 1st order reaction,

we know,

Tf = ln2/k

24 hrs = ln2/k

k= ln2/24

now,

in first order reaction ,

A --------> product

a 0. at t =0

a -x x at t =t°

now,

ln (a -x) = -kt +ln(a)

ln(a ) -ln(a -x) =kt

t = 1/k ln{a/(a -x)}

now,
put k = ln2/24
a = 10g
t =96 hrs

hence,

96 = 24/ln2.ln{10/(a -x)}

4ln2= ln{ 10/(a -x) }

ln(16) = ln{ 10/(a - x)}

16 = 10/(a -x)

(a -x) =10/16 = 0.63 g