What is the product obtained when the reaction of $CH_2-CH_2$ (epoxide) with $RMgX$ is followed by hydrolysis?

What is the order of reactivity for the reaction ${{C}_{2}}{{H}_{5}}OH + HX \xrightarrow{Zn{{X}_{2}}} {{C}_{2}}{{H}_{5}}X + {{H}_{2}}O$?

Suggest the reagent for the following conversion:

Which compound is soluble in water?

Identify the unknown $(A)$ in the reaction:

Which of the following compounds are not oxidized by $HIO_4$?
$(1)$ $CH_3-CH(OH)-CH_2-OH$
$(2)$ $CH_3-C(=O)-CHO$
$(3)$ $CH_3-C(=O)-C(=O)-CH_3$
$(4)$ $CH_3-C(=O)-CH(NH_2)-CH_3$
$(5)$ Cyclohexene oxide
$(6)$ $CH_3-O-CH_2-CH_2-OH$
$(7)$ $HOOC-CH_2-OH$