5. Solving a chemistry problem

134. The decomposition reaction of hydrogen iodine proceeds according to the equation 2HI(g)→H2(g)+I2(g) with a rate constant of 1.85*10-4 l/mol*s. Calculate: a) the time during which 99% of the starting substance will react if the initial concentration was 1 mol/s; b) HI half-life.