Answer
$K_{eq}$ = $\frac{[[H_{2}S]^{2} [CH_{4}]]}{[H_{2}]^{4} [CS_{2}]}$
Work Step by Step
To write an equation for the equilibrium constant, write the products with their coefficients as superscripts in the numerator of the expression, and likewise with the reactants with their coefficients as superscripts in the denominator of the expression.
