Question

Consider the zero order reaction
$R\to P$
Starting with 4 moles of R in a one litre container, after half an hour only 1 mole of R is left unreacted. The value of k for the reaction is:

• A. $0.1mol{L}^{-1}mi{n}^{-1}$
• B. $0.3mol{L}^{-1}mi{n}^{-1}$
• C. $1mol{L}^{-1}mi{n}^{-1}$
• D. $0.4mol{L}^{-1}mi{n}^{-1}$

Answer 1

The correct option is A $0.1mol{L}^{-1}mi{n}^{-1}$

Fall in concentration - 4 - 1 = 3 mol $L^{-1}$
Time taken = 30 min
For a zero order reaction
Rate = k
$\Rightarrow Rate=\frac{3mol{L}^{-1}}{30min}=0.1mol{L}^{-1}mi{n}^{-1}\Rightarrow k=0.1mol{L}^{-1}mi{n}^{-1}$