For the reaction $2 SO_2 + O_2 \rightleftharpoons 2 SO_3$,the units of $K_c$ are

For the following three reactions $a, b$ and $c,$ equilibrium constants are given:
$(i)$ $CO_{(g)} + H_2O_{(g)} \rightleftharpoons CO_{2(g)} + H_{2(g)}$ ; $K_1$
$(ii)$ $CH_{4(g)} + H_2O_{(g)} \rightleftharpoons CO_{(g)} + 3H_{2(g)}$ ; $K_2$
$(iii)$ $CH_{4(g)} + 2H_2O_{(g)} \rightleftharpoons CO_{2(g)} + 4H_{2(g)}$ ; $K_3$
Which of the following relations is correct?

For the given hypothetical reactions,the equilibrium constants are as follows:
$X \rightleftharpoons Y ; K_1=1.0$
$Y \rightleftharpoons Z ; K_2=2.0$
$Z \rightleftharpoons W ; K_3=4.0$
The equilibrium constant for the reaction $X \rightleftharpoons W$ is (in $.0$)

For the reaction $N_2 + 3H_2 \rightleftharpoons 2NH_3$,the equilibrium constant is $k$. What is the equilibrium constant for the reaction $2N_2 + 6H_2 \rightleftharpoons 4NH_3$?

The reaction,$2A_{(g)} + B_{(g)} \rightleftharpoons 3C_{(g)} + D_{(g)}$ is begun with the concentrations of $A$ and $B$ both at an initial value of $1.00 \ M$. When equilibrium is reached,the concentration of $D$ is measured and found to be $0.25 \ M$. The value for the equilibrium constant for this reaction is given by the expression:

For the reactions $SO_{2(g)} + \frac{1}{2}O_{2(g)} \rightleftharpoons SO_{3(g)}$ and $2SO_{3(g)} \rightleftharpoons 2SO_{2(g)} + O_{2(g)}$,if the equilibrium constants at $298 \ K$ are $K_1$ and $K_2$ respectively,then the correct relationship between them is .......