Which of the following statements is correct regarding the cathode of electrochemical cell ?

Which of the following solutions will have the highest electrical conductivity?

A first order reaction takes $16$ minutes for it's $50\%$ completion. What fraction that would react in $32$ minutes from the beginning?

The half-life of a first-order reaction is $20$ minutes. What is the rate constant (in min$^{-1}$) for this reaction?