For the first order reaction A(g)→2B(g)+C(g), the initial pressure is PA = 90 mm Hg, the pressure after 10 minutes is found to be 180 mm Hg. The rate constant of the reaction is

Question

For the first order reaction A(g)→2B(g)+C(g), the initial pressure is PA = 90 mm Hg, the pressure after 10 minutes is found to be 180 mm Hg. The rate constant of the reaction is (A) 1.15 × 10-3 sec-1 (B) 2.3 × 10-3 sec-1 (C) 3.45 × 10-3 sec-1 (D) 6 × 10-3 sec-1

Tardigrade Admin · Accepted Answer

<img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/chemistry/c0049f40ca662f9e94619e485d4a606d-.png" /> Total pressure after 10 minutes, PT= PA + PB + Pc or Pt=(PA-x)+2x+x =pA+2x=180 ∵ PA=90 mm 90+2x=180 or X=45mm ∴ PA-x=90-45=45mm kt=2.303 log (PA/PA-x) or k×10=2.303 log (90/90-45) k×10=0.693 or k=(0.693/10)=0.0693 min-1 =(0.693/10×60 sec)=1.155×10-1sec-1

Q. For the first order reaction $A (g) \to 2 B (g) + C (g),$ the initial pressure is $P_{A} = 90 mm H g,$ the pressure after 10 minutes is found to be $180 mm H g$ . The rate constant of the reaction is

$1.15 \times 1 0^{- 3} se c^{- 1}$

$2.3 \times 1 0^{- 3} se c^{- 1}$

$3.45 \times 1 0^{- 3} se c^{- 1}$

$6 \times 1 0^{- 3} se c^{- 1}$

Q. For the first order reaction A(g)→2B(g)+C(g), the initial pressure is PA​=90mmHg, the pressure after 10 minutes is found to be 180mmHg. The rate constant of the reaction is

1.15×10−3sec−1

2.3×10−3sec−1

3.45×10−3sec−1

6×10−3sec−1

Total pressure after 10 minutes, PT​=P​A+PB​+Pc​ or Pt​=(PA​−x)+2x+x =pA​+2x=180 ∵PA​=90mm 90+2x=180orX=45mm ∴PA​−x=90−45=45mm kt=2.303logPA​−xPA​​ or k×10=2.303log90−4590​ k×10=0.693 or k=100.693​=0.0693min−1=10×60sec0.693​=1.155×10−1sec−1

Q. For the first order reaction $A (g) \to 2 B (g) + C (g),$ the initial pressure is $P_{A} = 90 mm H g,$ the pressure after 10 minutes is found to be $180 mm H g$ . The rate constant of the reaction is

$1.15 \times 1 0^{- 3} se c^{- 1}$

$2.3 \times 1 0^{- 3} se c^{- 1}$

$3.45 \times 1 0^{- 3} se c^{- 1}$

$6 \times 1 0^{- 3} se c^{- 1}$