The product obtained by the reaction of ethyl bromide with alcoholic silver nitrite is .............. .

$A$ dihalogen derivative '$X$' of a hydrocarbon with three carbon atoms reacts with alcoholic $KOH$ to give another hydrocarbon which forms a red precipitate with ammoniacal $Cu_2Cl_2$. '$X$' gives an aldehyde upon reaction with aqueous $KOH$. What is the compound '$X$'?

Ethyl chloride on heating with silver cyanide forms a compound $X$. The functional isomer of $X$ is

Which of the following undergoes nucleophilic substitution by $S_N1$ mechanism?

Which compounds give $\beta$-elimination reactions? What are their main products?

Increasing the concentration of an electrophile (substrate) in a typical $S_N2$ reaction by a factor of $3$ and the concentration of the nucleophile by a factor of $3$ will change the reaction rate to