The product of the reaction is:

What is the final product $(B)$ of this sequence?

What are $\underline{A}, \underline{B}, \underline{C}$ in the following reactions?
$(I)$ $(CH_3 CO_2)_2 Ca \stackrel{\Delta}{\longrightarrow} \underline{A}$
$(II)$ $CH_3 CO_2 H \underset{\text{Red P}}{\stackrel{HI}{\longrightarrow}} \underline{B}$
$(III)$ $2 CH_3 CO_2 H \stackrel{P_4 O_{10}}{\longrightarrow} \underline{C}$
$\underline{A} \quad \underline{B} \quad \underline{C}$

$C_6H_6$ $\xrightarrow[AlCl_3]{(CH_3)_2CHCOCl}$ $\xrightarrow[\text{reduction}]{\text{Clemmensen}}$ $\xrightarrow[AlCl_3]{CH_3COCl}$ $\xrightarrow[\text{Red } P + HI]{H_3O^{\oplus}} (\text{Ibuprofen})$
Ibuprofen is

The major product in the following reaction is

The number of methoxy groups in a compound can be determined by treating it with