Explanation:

A balanced chemical equation has the same number of atoms of each element on both sides of the equation. This means the equation obeys the law of conservation of mass, which states that matter cannot be created or destroyed, only transformed.

Option C is not a balanced chemical equation because the number of chlorine atoms is not the same on both sides of the equation. The left side has one chlorine atom (from Cl2) while the right side has two chlorine atoms (from FeCl2).

Let's break down each option to see which ones are balanced equations:

a) Mg(s) + CuSO4(aq) → MgSO4(aq) + Cu(s)
This is a balanced chemical equation. On the left side, we have one magnesium atom and one copper atom. On the right side, we also have one magnesium atom and one copper atom. We also have one sulfur atom and four oxygen atoms on both sides.

b) Zn(s) + H2SO4(aq) → ZnSO4(aq) + H2(g)
This is also a balanced chemical equation. On the left side, we have one zinc atom and two hydrogen atoms. On the right side, we have one zinc atom and two hydrogen atoms. We also have one sulfur atom and four oxygen atoms on both sides.

c) Fe(s) + Cl2(g) → FeCl2(s)
As mentioned earlier, this is not a balanced chemical equation because the number of chlorine atoms is different on both sides.

d) Ca(OH)2(l) + CO2(g) → CaCO3(s) + H2O(l)
This is a balanced chemical equation. On the left side, we have one calcium atom, two hydrogen atoms, one carbon atom, and two oxygen atoms. On the right side, we have one calcium atom, one carbon atom, and three oxygen atoms. We also have two hydrogen atoms and one oxygen atom on both sides (from the water molecule).

Therefore, the correct answer is option C, which is not a balanced chemical equation.

D will be correct option there are 4 atoms of oxygen in reactant but in product, it is only 2 atom of oxygen .so D is right .