Which of the following is a lachrymatory agent or tear gas?

Identify the test from the following in which an aldehyde,when boiled with an ammoniacal silver nitrate solution,deposits silver.

In the following reactions,$P, Q, R$,and $S$ are the major products.
The correct statement$(s)$ about $P, Q, R$,and $S$ is(are):
$(A)$ Both $P$ and $Q$ have asymmetric carbon$(s)$.
$(B)$ Both $Q$ and $R$ have asymmetric carbon$(s)$.
$(C)$ Both $P$ and $R$ have asymmetric carbon$(s)$.
$(D)$ $P$ has asymmetric carbon$(s)$,$S$ does not have any asymmetric carbon.

Compound $(A)$ with molecular formula $C_6H_{12}O_3$ gives a positive iodoform test and a negative Tollens' test. Upon hydrolysis with a drop of $H_2SO_4$,it gives a product that shows a positive Tollens' test. Compound $(A)$ is:

Which among the following is a possible product during cross aldol condensation between propanal (as electrophile) and butanal (as nucleophile)?

The given reaction is an example of an intramolecular aldol condensation. Identify the product $(A)$ formed in the reaction:
$1,5-\text{cyclooctanedione} \xrightarrow{H_2SO_4, H_2O} (A)$