1. Tardigrade
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  3. Chemistry
  4. For the reaction 2H2(g)+2NO(g) arrow N2(g)+2H2O(g) the observed rate expression is, rate =kf [NO]2[H2]. The rate expression for the reverse reaction is :

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Q. For the reaction
$2H_{2}\left(g\right)+2NO\left(g\right) \rightarrow N_{2}\left(g\right)+2H_{2}O\left(g\right)$
the observed rate expression is, rate $=k_{f} \left[NO\right]^{2}\left[H_{2}\right]$. The rate expression for the reverse reaction is :

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Solution:

Given reaction is,
$2 H _{2}( g )+2 NO ( g ) \rightarrow N _{2}( g )+2 H _{2} O ( g )$
$r _{ f }= k _{ f }[ NO ]^{2}\left[ H _{2}\right]$
Now,
$K _{ eq }=\frac{ k _{ f }}{ k _{ b }}=\frac{\left[ N _{2}\right] \times\left[ H _{2} O \right]^{2}}{\left[ H _{2}\right]^{2} \times[ NO ]^{2}}$
Rearranging the above equation,
$k _{ f }[ NO ]^{2}\left[ H _{2}\right]$
$=k _{ b } \frac{\left[ N _{2}\right]\left[ H _{2} O \right]^{2}}{\left[ H _{2}\right]}$
$\Rightarrow r _{ f }= r _{ b }$
$\Rightarrow r _{ b }= k _{ b } \frac{\left[ N _{2}\right]\left[ H _{2} O \right]^{2}}{\left[ H _{2}\right]}$