Compound $A$ $(C_9H_{10}O)$ shows a positive iodoform test. Oxidation of $A$ with $KMnO_4/KOH$ gives acid $B$ $(C_8H_6O_4)$. The anhydride of $B$ is used for the preparation of phenolphthalein. Compound $A$ is:

Aldol condensation will not be observed in

Which pair of reactant compounds may be used to make the given acetal?

Which is the best oxidizing agent to oxidize $CH_3CH=CHCHO$ to $CH_3CH=CHCOOH$?

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$ : $Image-I$ can be easily reduced using $Zn-Hg / HCl$ to $Image-II$.
Reason $R : Zn-Hg / HCl$ is used to reduce carbonyl group to $-CH_2-$ group.
In the light of the above statements,choose the correct answer from the options given below:

The reaction of chloroform with acetone gives ...................