Question

A first order reaction in aqueous solution was too fast to be detected by a procedure that could have followed a reaction having a half life of at least 2.0ns. The minimum value of the rate constant of the reaction is

• A. $3.5\times {10}^8{s}^{-1}$
• B. $1.2\times {10}^8{s}^{-1}$
• C. $1.9\times {10}^8{s}^{-1}$
• D. $2.7\times {10}^8{s}^{-1}$

Answer 1

The correct option is A $3.5\times {10}^8{s}^{-1}$

$k=\frac{0.693}{T_{\frac{1}{2}}}=\frac{0.693}{2\times {10}^{-9}}=3.46\times {10}^8{s}^{-1}$