Before using chloroform as an anesthetic,its sample is tested by ........

$S_N1$ reactions are generally carried out in which type of solvents?

In the reaction of $1$-vinyl-$-2$-bromoethylbenzene with $HBr$,the major product is:

Which of the following phrases are not correctly associated with $S_N1$ reaction?
$(1)$ Rearrangement is possible
$(2)$ Rate is affected by polarity of solvent
$(3)$ The strength of the nucleophile is important in determining rate
$(4)$ The reactivity series is tertiary $>$ secondary $>$ primary
$(5)$ Proceeds with complete inversion of configuration

Arrange the compounds of each set in order of reactivity towards $S_{N}2$ displacement:
$(i)$ $2-Bromo-2-methylbutane$,$1-Bromopentane$,$2-Bromopentane$
$(ii)$ $1-Bromo-3-methylbutane$,$2-Bromo-2-methylbutane$,$2-Bromo-3-methylbutane$
$(iii)$ $1-Bromobutane$,$1-Bromo-2,2-dimethylpropane$,$1-Bromo-2-methylbutane$,$1-Bromo-3-methylbutane$.

$A$ chloro compound $A$:
$(i)$ forms aldehydes on ozonolysis followed by hydrolysis.
$(ii)$ when vaporized completely,$1.53 \ g$ of $A$ gives $448 \ mL$ of vapour at $STP$.
The number of carbon atoms in a molecule of compound $A$ is ...... .