The rate constant of a first order reaction is 1.15 10⁻³ ~s ⁻¹ . How long will 5 g of reactant take to reduce to 3 g ?

Step-by-step solution

The integrated rate law for a first-order reaction is: t = 2.303 k [A]₀ [A]_t . Given k = 1.15 10⁻³ , s ⁻¹ , [A]₀ = 5 , g , and [A]_t = 3 , g , substitute into the formula to obtain: t = 2.303 1.15 10⁻³ ( 5 3 ) . The ratio 5 3 1.6667 , and (1.6667) 0.2218 . With this, the expression becomes: t = 2.303 0.2218 1.15 10⁻³ = 0.5108 0.00115 444 , s . Matching the result with the options, the correct choice is D .