A bottle is labelled hydrochloric acid, 36 % by mass, density 1.18 g/mL…

Step 1. Moles. HCl: $\dfrac{36}{36.5} = 0.9863\ \text{mol}$. Water: $\dfrac{64}{18} = 3.556\ \text{mol}$.

Step 2. Volume. $\dfrac{100\ \text{g}}{1.18\ \text{g/mL}} = 84.75\ \text{mL} = 0.08475\ \text{L}$.

Step 3. Molarity. $\dfrac{0.9863\ \text{mol}}{0.08475\ \text{L}} = 11.64\ \text{mol/L}$.

Step 4. Molality. $\dfrac{0.9863\ \text{mol}}{0.064\ \text{kg}} = 15.41\ \text{mol/kg}$.

Step 5. Mole fraction. $x = \dfrac{0.9863}{0.9863 + 3.556} = 0.2172$.