Which of the following functional groups is present in aldehyde compounds?

Carbon,a Group $14$ element in the Periodic Table,is known to form compounds with many elements. Write an example of a compound formed with:
$(a)$ Chlorine (Group $17$ of Periodic Table)
$(b)$ Oxygen (Group $16$ of Periodic Table)

The oxidising agent which can oxidise ethanol to ethanoic acid is:

Which polymer is used in controlled-release drug capsules?

$A$ colourless gas '$X$' has a formula $C_{3}H_{6}$. It decolourises bromine water. Write the chemical name of '$X$'.

Look at the figure and answer the following questions:
$(a)$ What change would you observe in the calcium hydroxide solution taken in tube $B$?
$(b)$ Write the chemical reactions involved in test tubes $A$ and $B$ respectively.