For a reaction of order

Question:

For a reaction of order $\mathrm{n}$, the unit of the rate constant is :

  1. $\mathrm{mol}^{1-\mathrm{n}} \mathrm{L}^{1-\mathrm{n}} \mathrm{S}$

  2. $\mathrm{mol}^{1-\mathrm{n}} \mathrm{L}^{2 \mathrm{n}} \mathrm{s}^{-1}$

  3. $\mathrm{mol}^{1-\mathrm{n}} \mathrm{L}^{\mathrm{n}-1} \mathrm{~s}^{-1}$

  4. $\mathrm{mol}^{1-\mathrm{n}} \mathrm{L}^{1-\mathrm{n}} \mathrm{s}^{-1}$


Correct Option: , 3

Solution:

Rate $=\mathrm{k}[\mathrm{A}]^{\mathrm{n}}$

comparing units

$\frac{(\mathrm{mol} / \ell)}{\mathrm{sec}}=\mathrm{k}\left(\frac{\mathrm{mol}}{\ell}\right)^{\mathrm{n}}$

$\Rightarrow \mathrm{k}=\mathrm{mol}^{(1-\mathrm{n})} \ell^{(\mathrm{n}-1)} \mathrm{s}^{-1}$

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