The sulfur strip started burning after a certain time. The burning sulfur combined with oxygen from the air and sulfur dioxide was formed.
S(s) + O2(g) -->SO2(g)
A bluish fog (smoke) also appeared when the sulfur strip burned. The edges of the petals have turned white. The color of the indicator, after being dipped in water, changes color to orange, and the pH reading is equal to 4.5, and this is because sulfuric acid is formed. SO2 + H20 --> H2SO3
The candle burns, the air inside the glass heats up, causing it to expand, causing pressure to build up inside the glass. When the candle is extinguished, the air begins to cool and contract, leading to a decrease in pressure. Since the pressure inside the glass after burning the candle is lower than atmospheric, air from outside tries to enter the glass in order to equalize the pressures, while water enters the glass.
