The molecular formula of compound $A$ is $C_2Cl_3OH$. It reduces Fehling's solution and on oxidation gives a monocarboxylic acid $B$. Compound $A$ is obtained by the reaction of chlorine with ethyl alcohol. What is $A$?

Which of the following statements is incorrect?

Assertion : Aldol condensation can be catalysed both by acids and bases.
Reason : $\beta$-Hydroxyaldehydes or ketones readily undergo acid-catalysed dehydration.

The polymer shown in the image is obtained when a carbon compound is allowed to stand. It is a white solid. The polymer is:

Arrange the following compounds in increasing order of their reactivity in nucleophilic addition reactions.
$(i)$ Ethanal,Propanal,Propanone,Butanone.
$(ii)$ Benzaldehyde,$p-$Tolualdehyde,$p-$Nitrobenzaldehyde,Acetophenone.
Hint: Consider steric effect and electronic effect.

Describe the various chemical reactions of aldehyde and ketone compounds.