Explain the differences in observations when magnesium ribbon and potassium manganate (VII) are heated in air.

I need some additional information to solve parts (iii), (iv), and (v) of question 1. The image provided does not contain the concentration of the solution that reacted with solution X in the titration, nor the initial mass of X used to prepare the 250 $\text{cm}^3$ solution. Without this information, I cannot calculate the moles, molar mass, or concentration of solution X.

---

PART B

2. In an experiment magnesium ribbon was heated in air. The product formed was found to be heavier than the original ribbon. Potassium manganate (VII) was on the other hand, heated in air and product formed was found to be lighter. Explain the differences on the observation made.

When magnesium ribbon is heated in air, it reacts with oxygen from the air to form magnesium oxide. The mass of the oxygen adds to the mass of the magnesium, making the product heavier than the original ribbon.

$$2\text{Mg}(s) + \text{O}_2(g) \rightarrow 2\text{MgO}(s)$$

When potassium manganate (VII) is heated in air, it decomposes to form potassium manganate (VI), manganese (IV) oxide, and oxygen gas. The oxygen gas escapes, causing the solid products to be lighter than the original potassium manganate (VII).

$$2\text{KMnO}_4(s) \rightarrow \text{K}_2\text{MnO}_4(s) + \text{MnO}_2(s) + \text{O}_2(g)$$

3. In a titration experiment 25$\text{cm}^3$ of a solution of Sodium Hydroxide containing 8g per litre was required for complete neutralization of 0.245g of a dibasic acid. Calculate the relative molecular mass of the acid (Na = 23.0, O = 16, H = 1).