A Form Three student carried out an experiment and obtained the following data and recorded as in the table below; answer the questions that follow. a) Complete the table above.

• For $V=15$: $P \times 15 = 300 \Rightarrow P = \frac{300}{15} = 20$.
• For $V=12$: $P \times 12 = 300 \Rightarrow P = \frac{300}{12} = 25$.
• For $V=10$: $P \times 10 = 300 \Rightarrow P = \frac{300}{10} = 30$.

• For $P=5$: $1/5 = 0.20$.
• For $P=10$: $1/10 = 0.10$.
• For $P=15$: $1/15 \approx 0.0667$.
• For $P=20$: $1/20 = 0.05$.
• For $P=25$: $1/25 = 0.04$.
• For $P=30$: $1/30 \approx 0.0333$. (The table has 0.03, which is an approximation).

The completed table is:

b) Draw a sketch of the expected graph of volume against $1/P$.
The graph of volume ($V$) against the reciprocal of pressure ($1/P$) would be a straight line passing through the origin. This is because $V = k \times (1/P)$, which is in the form $y = mx$. Volume (V) ^ | / | / | / | / +-----------> 1/Pressure (1/P) 0

c) Explain the graph obtained.
The graph is a straight line passing through the origin, which shows that the volume of a fixed mass of gas is directly proportional to the reciprocal of its pressure at constant temperature. This observation is consistent with Boyle's Law.

10. In an investigation, Sulphur (IV) oxide gas was bubbled through acidified bromine water. This was followed by drops of Barium nitrate solution. a) State the property of sulphur (IV) oxide under investigation. The property of sulphur (IV) oxide under investigation is its reducing property (it acts as a reducing agent).

    b) State and explain the observations made on addition of Sulphur (IV) Oxide into the bromine water.
    Observation: The reddish-brown color of the bromine water disappears (it is decolorized).
    Explanation: Sulphur (IV) oxide ($\text{SO}_2$) reduces the reddish-brown bromine ($\text{Br}_2$) to colorless bromide ions ($\text{Br}^-$), while itself being oxidized to sulfate ions ($\text{SO}_4^{2-}$).

    $$\text{SO}_2\text{(g)} + \text{Br}_2\text{(aq)} + 2\text{H}_2\text{O(l)} \rightarrow \text{H}_2\text{SO}_4\text{(aq)} + 2\text{HBr(aq)}$$

11. Write the observations and the equation of the reactions which occur when concentrated sulphuric (VI) acid reacts with each of the following: a) Sugar Observation: The white sugar turns black and swells up, forming a porous mass of carbon. Steam is also produced. Equation:

    $$\text{C}_{12}\text{H}_{22}\text{O}_{11}\text{(s)} \xrightarrow{\text{conc. H}_2\text{SO}_4} 12\text{C(s)} + 11\text{H}_2\text{O(l)}$$

    b) Copper (II) sulphate crystals
    Observation: The blue crystals turn