• # question_answer Decomposition of A follows first order kinetics by the following equation. $4A(g)\xrightarrow{{}}B(g)+2C(g)$ If initially, total pressure was 800 mm of Hg and after 10 minutes it is found to be 650 mm of Hg. What is half-life of A? (Assume only A is present initially). A) 10 mins B) 5 mins C) 7.5 mins D) 15 mins

 $4A(g)\xrightarrow{{}}$ B(g)  + 2C(g) t = 0 800 $-$ $-$ t = 10 minutes, 800 - 4p p 2p
800 - p = 650 $\therefore$      p = 150 Pressure of A = 200, so $\therefore$      $2\times {{t}_{1/2}}=10$ minutes ${{t}_{1/2}}=5$ minutes