For a gaseous reaction, the rate is expressed in terms of dP/dt in place of dC/dt or dn/dt, where C is concentration, n is number of moles and ′P′ is pressure of reactant. The three are related as -

Correct answer: (B) 1/RTdP/dt=1/Vdn/dt=dC/dt. Rate=dC/dt C=n/V and C=P/RT dC/dt=d/dtn/V=1/V×dn/dt d/dtP/RT=1/RT×dP/dt

Q50 / 196 · NTA Abhyas (NEET) 2020 · Chemistry · Chemical Kinetics

For a gaseous reaction, the rate is expressed in terms of $\frac{d P}{d t}$ in place of $\frac{d C}{d t}$ or $\frac{d n}{d t}$ , where $C$ is concentration, $n$ is number of moles and $' P'$ is pressure of reactant. The three are related as -

A
$[\frac{d P}{d t}] = \frac{R T}{V} [\frac{d n}{d t}] = [\frac{d C}{d t}]$
Correct answer
B
$\frac{1}{R T} [\frac{d P}{d t}] = \frac{1}{V} [\frac{d n}{d t}] = [\frac{d C}{d t}]$
C
$[\frac{d P}{d t}] = [\frac{d n}{d t}] = [\frac{d C}{d t}]$
D
None of these

R a t e = \frac{d C}{d t}

C = \frac{n}{V}

and

C = \frac{P}{R T}

\frac{d C}{d t} = \frac{d}{d t} (\frac{n}{V}) = \frac{1}{V} \times (\frac{d n}{d t})

\frac{d}{d t} (\frac{P}{R T}) = \frac{1}{R T} \times (\frac{d P}{d t})

Hence, the correct answer is option: 'B'.