Identify A and B in the following reactions :
(1) CH3MgI + CH3COCH3 → A \( \overset{dil.}{\underset{HCl}{\longrightarrow}}\) B + MgICl
(2) CH3MgBr \(\overset{CH_3CN}{\longrightarrow}\) A \( \overset{HOH}{\underset{H^+}{\longrightarrow}}\) B + NH3 + MgBrOH