What is the product of the following reaction?

An organic compound $A$ on reaction with $PCC$ $(\text{Pyridinium chlorochromate})$ gives a compound $B$. $B$ on further reaction with $I_2$ and $NaOH$ forms tri-iodomethane. Identify the compound $A$.

Toluene $\xrightarrow[(2) \ H_3O^{+}]{(1) \ CrO_2Cl_2 / CS_2} X$ $\xrightarrow{\text{Conc. } NaOH} Y + Z$. The correct statements about $Y$ and $Z$ are:
$A. \quad Y$ is a secondary alcohol
$B. \quad Y$ is the reduction product of $X$
$C. \quad Z$ on heating with soda lime gives benzene
$D. \quad Y$ does not give $H_2$ gas with $Na$ metal

Which of the following compounds is responsible for the iodoform reaction?

Write a note on addition compounds of alcohol in aldehyde and ketone. $OR$ What are hemiacetal,acetal and ketal compounds? Give examples.

$A \xrightarrow{} (CH_3)_2C=CH-CO-CH_3$. $A$ is: