Question

Which is correct relation in between $-\frac{d C}{d t},-\frac{d n}{d t}$, and $-\frac{d P}{d t}$ where $C, n, P$, represents concentration, mole, and pressure terms for gaseous phase reactant $A ( g ) \rightarrow$ Product:

• A. $-\frac{d C}{d t}$ and $=-\frac{1}{V} \frac{d n}{d t}=-\frac{1}{R T} \frac{d P}{d t}$
• B. $-\frac{d C}{d t}=-\frac{d n}{d t}=-\frac{d P}{d t}$
• C. $-\frac{d C}{d t}=-\frac{R T}{V} \frac{d n}{d t}=-\frac{d P}{d t}$
• D. all of these.

Answer 1

Answer: (A)

Rate $=-\left[\frac{d C}{d t}\right]=\left[-\frac{d n}{d t}\right] \frac{1}{V}$
$ \because C=\frac{n}{v}$
Also $C=\frac{P}{R T}$
$\therefore -\left[\frac{d C}{d t}\right]=-\frac{1}{R T}\left[\frac{d p}{d t}\right]$