What is added to chloroform to prevent it from becoming toxic when used as an anesthetic?

The major product obtained in the following reaction is $C_2H_5ONa + (CH_3)_3C-Cl \rightarrow$

The relation between $(A)$ and $(B)$ is:

Consider the following reaction,
$C_2H_5Cl + AgCN \xrightarrow{EtOH / H_2O} \underline{X} \text{ (major)}$
Which one of the following statements is true for $\underline{X}$?
$(I)$ It gives propionic acid on hydrolysis
$(II)$ It has an ester functional group
$(III)$ It has a nitrogen linked to ethyl carbon
$(IV)$ It has a cyanide group

Which of the following chloro-compounds shows complete inversion of configuration during a reaction?

$Ph-CH(Br)-CH_2-CH_2-Br \xrightarrow[\Delta]{Zn-Cu} \text{Product}$. The product of the above reaction is: