Balance the following equation stepwise: H2S2O7(l) + H2O(l) → H2SO4(l)

Balanced equation: \(\mathrm{H_2S_2O_7(l) + H_2O(l) \rightarrow 2H_2SO_4(l)}\)

Step 1: Count atoms in the skeletal equation.

Step 2: Sulphur is 2 on the left and 1 on the right, so put coefficient 2 before \(\mathrm{H_2SO_4}\).

Step 3: Recount. Right side now has H = 4, S = 2, O = 8, which matches the left side exactly.

So the balanced equation is \(\mathrm{H_2S_2O_7 + H_2O \rightarrow 2H_2SO_4}\). (Oleum reacts with water to give sulphuric acid.)