CBSE 2023 · Region 5 · Set 1 · Q13 · 1 mark

The following experimental rate data were obtained for a reaction carried out at $\displaystyle 25$ °C : $\displaystyle \mathrm{A}_{(\mathrm{g})}+\mathrm{B}_{(\mathrm{g})} \rightarrow \mathrm{C}_{(\mathrm{g})}+\mathrm{D}_{(\mathrm{g})}$

Initial $\displaystyle \left[\mathrm{A}_{(\mathrm{g})}\right] / \mathrm{mol} \mathrm{dm}^{-3}$	Initial $\displaystyle \left[\mathrm{B}_{(\mathrm{g})}\right] / \mathrm{mol} \mathrm{dm}^{-3}$	Initial rate/mol $\displaystyle \mathrm{dm}^{-3} \mathrm{~s}^{-1}$
$\displaystyle 3.0 \times 10^{-2}$	$\displaystyle 2.0 \times 10^{-2}$	$\displaystyle 1.89 \times 10^{-4}$
$\displaystyle 3.0 \times 10^{-2}$	$\displaystyle 4.0 \times 10^{-2}$	$\displaystyle 1.89 \times 10^{-4}$
$\displaystyle 6.0 \times 10^{-2}$	$\displaystyle 4.0 \times 10^{-2}$	$\displaystyle 7.56 \times 10^{-4}$

What are the orders with respect to $\displaystyle \mathrm{A}_{(\mathrm{g})}$ and $\displaystyle \mathrm{B}_{(\mathrm{g})}$ ?

(a)

Order with respect to $\displaystyle \mathrm{A}_{(\mathrm{g})}$	Order with respect to $\displaystyle \mathrm{B}_{(\mathrm{g})}$
Zero	Second
First	Zero
Second	Zero
Second	First

CBSE Class 12 Chemistry past-paper question from the 2023board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.