Which of the following is the correct equilibrium constant expression for the reversible chemical reaction AlNO3 + NaCl <-- --> NaNO3 + AlCl.

A. Keq= ([NaNo3] x [AlNO3]) / ([AlCl] x [NaCl])
B. Keq= ([NaCl] x [AlCl]) / ([AlNO3] x [NaNO3])
C. Keq= ([NaNo3] x [AlCl]) / ([AlNO3] x [NaCl])
D. Keq= ([AlNO3] x [NaCl]) / ([NaNO3] x [AlCl])

Option c.

Be careful, because you have wrong compounds

Explanation:

Our equilibrium is:

Al(NO₃)₃ + 3NaCl ⇄ 3NaNO₃ + AlCl₃

To determine the Kc,  the molar concentrations of the products is multiplied, and they are raised to what the stoichiometry indicates and divided by the products of the reactants, which are also raised according to the stoichiometry. We can see this example

aA + bB ⇄ xC + nD

Kc expression will be: [C]ˣ . [D]ⁿ / [B]ᵇ . [A]ᵃ

If we do not have stoichiometry, you know we have a 1.

The expression for Kc, in the equilibrium proposed is:

Kc = [AlCl₃] . [NaNO₃]³ /  [NaCl]³ . [Al(NO₃)₃]