First order reacton ha specific rate of `10^(-3) s ^(-1).` How much time will it take for 10 g of the reactant to reduce to 5 g ?

Explanation

We are given that
`k = 10 ^(-3) s ^(-1) , a = 10 g `
`a - x = 5 g `
We are to find out t
Using the reaction ,` t = ( 2. 303)/(k )log ""(a)/( (a -x))" "...(i)`
`therefore t = ( 2. 303 )/( 10 ^(-3) s ^(-1)) log "" (10 g )/( 5 g) = 2. 303 xx 10 ^(3) log 2 . 2. 303 xx 10 ^(3) xx 0. 3010 = 693. 20 s `