1. Tardigrade
  2. Question
  3. Chemistry
  4. Given that, Ka( HCN )=4.9 × 10-10, Ka( HNO 2)=4.5 × 10-4 Thus, which of the following reaction is favoured in forward direction?

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Q. Given that, $K_{a}( HCN )=4.9 \times 10^{-10}, K_{a}\left( HNO _{2}\right)=4.5 \times 10^{-4}$ Thus, which of the following reaction is favoured in forward direction?

Equilibrium

Solution:

$K_{a}\left( HNO _{2}\right)>\,K_{a}( HCN )$

Larger the value of $K_{a}$, stronger is the acid. Thus, $HNO _{2}$ is stronger acid than $HCN . NO _{2}^{-}$ is a weaker base than $CN^-$. $HNO _{2}$ is better proton donor and $CN^-$ is better proton acceptor. Thus, (b) is favoured in forward side (in which weaker acid and weaker base are formed).