Here's how to balance the chemical equation for the reaction of mercury(II) nitrate and sodium chloride:

1. Write the unbalanced equation:

Hg(NO₃)₂ (aq) + NaCl (aq) → HgCl₂ (s) + NaNO₃ (aq)

2. Identify the reactants and products:

* Reactants: Mercury(II) nitrate (Hg(NO₃)₂) and sodium chloride (NaCl)

* Products: Mercury(II) chloride (HgCl₂) and sodium nitrate (NaNO₃)

3. Balance the equation by adjusting coefficients:

* Start with the mercury (Hg): One Hg on each side, so it's balanced.

* Next, balance the chloride (Cl): Two Cl on the product side (HgCl₂), so we need two NaCl on the reactant side.

* Now balance the nitrate (NO₃): Two NO₃ on the reactant side (Hg(NO₃)₂), and we need two NO₃ on the product side, so we put a 2 in front of NaNO₃.

The balanced equation is:

Hg(NO₃)₂ (aq) + 2 NaCl (aq) → HgCl₂ (s) + 2 NaNO₃ (aq)