Consider the following sequence of reactions.
$1$-methylindene $\xrightarrow[NaHSO_3]{OsO_4} A$ $\xrightarrow[2. NaOH, \text{heat}]{1. HIO_4} B$
The final product $(B)$ is

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 $A$.

$(A)$ and $(B)$ in the following reaction sequence are:
$RR'C=O$ $\xrightarrow{HCN} (A)$ $\xrightarrow{B} RR'C(OH)CH_2NH_2$

The total number of $sp^2$ hybridised carbon atoms in the major product $P$ (a non-heterocyclic compound) of the following reaction is. . . . . . .

Which of the following gives a positive iodoform test? The reaction is shown below:
$2,3,5-\text{trimethylhepta-2,4-diene} \xrightarrow[(2) H_2O/Zn]{(1) O_3} X (C_3H_6O) + Y (C_3H_4O_2) + Z (C_2H_4O)$

Mandelonitrile is obtained by the reaction between hydrogen cyanide and