Question

For the reaction, $A\left(g\right)+2B\left(g\right)⟶C\left(g\right)+D\left(g\right)$
$\frac{dx}{dt}=k\left[A\right]{\left[B\right]}^2$
Initial pressure of A and B are respectively $0.60$atm and $0.80$atm, At a time when the pressure of C is $0.20$atm, rate of the reaction, relative to the initial value is:

• A. $\frac{1}{6}$
• B. $\frac{1}{48}$
• C. $\frac{1}{4}$
• D. $\frac{1}{24}$

Answer 1

Answer: (A)

$\frac{1}{6}$

Initially According to the Rate Equation and the given values

$Rate=k\left[0.6\right]{\left[0.8\right]}^2$

When the pressure of C is 0.2 atm, Then the pressure of A becomes $0.6-0.2=0.4$ atm and Pressure of B becomes $0.8-2\times 0.2=0.4$ atm

So, the new rate becomes

$Rate=k\left[0.4\right]{\left[0.4\right]}^2$

Ratio of New rate to Initial rate = $\frac{1}{6}$