Identify that an organic compound displays characteristic chemical properties and undergoes specific reactions based on the functional group present.

Which functional group in the compound shown below would undergo rapid addition of bromine in carbon tetrachloride (CCl₄) under room temperature, producing a decolourisation of the reddish-brown solution?

Which of the following compounds would readily undergo addition polymerisation?

A student is given a compound with the structural formula shown below. $$\ce{CH3CH2CH2COOH}$$ Identify the functional group present in this compound and state one characteristic chemical reaction that this functional group undergoes.