Question

In case of which of the following equilibria $K_c$ has no units ?

• A. Formation of nitric oxide from the elements
• B. Formation of ammonia from the elements
• C. Formation of $S{O}_3$ by oxidation of its lower oxide
• D. Both $B$ and $C$

Answer 1

The correct option is A Formation of nitric oxide from the elements

$K_c$ will have no unit if the number of moles of reactant are same as product

$N_2+O_2\to 2NO$; 2mol gives 2 mol

$N_2+3H_2\to 2N{H}_3$; 4mol gives 2 mol

$2S{O}_2+O_2\to 2S{O}_3$; 3mol gives 2 mol

therefore A is correct.